SUPERNOTES.TXT

http://bit.ly/2QGHDCh

What is Kubernetes?
    Container orch tool.



What is Docker?
------------------
Container - Management - tool
OPEN SOURCE
FREE
RELEASE 
     - Docker CE - FREE
     - Docker EE - PAID
     https://www.docker.com/products/docker-enterprise

What is Container?
---------------------

20 YEARS -----> RUN APP
================================
PHYSICAL MACHINE 
    CPU + RAM + HDD + OS ---> APP
----------------------------------
-- 10 USERS -- 1 APP -- 1 PHYSCIAL 
-- 1000 USERS --- 1 APP --- 10 PHYSICAL MACHINE.
=================================================
            - HIGH AVAILABILILITY
            - SCALIBILYT
            - Security

=======================================================
REDUCE A SOFtWARE RUNNING?
            WASTAGE IN COMPUTING
1 PHYSICAL
        1 CPU   --> 15%---80%%%
        1 RAM
        1 HDD
        1 OSS
-----------------------
2000 PHYSICAL --- 80%
==================================
            VIRUALIZATION

WASTAGE ---- nOT MORE than 15%
==========================================
Demo 
35.154.121.235

How to install docker in RHEL 7.X
====================================
https://www.devopsschool.com/tutorial/docker/install-config/docker-install-commuityedition-centos-rhel.html

Working with Containers?
-----------------------


Working with Docker Images?
-------------------------



Sharing Images
-------------------








What is Kubernetes?
    Container orch tool.

alexmatt
ChinmoyPadhi
ksvijayb
vijaynathani77
Ahamedukhan
anilkpo
anil1205
vengam
vjegadeesan
babafakruddin476
revanth-wgl
VasanthBruce
imsandeepg
gkshrikant
reddyko
mohapma

What is Docker?
------------------
Container - Management - tool
OPEN SOURCE
FREE
RELEASE 
     - Docker CE - FREE
     - Docker EE - PAID
     https://www.docker.com/products/docker-enterprise
Solomon Hykyes
Go
https://www.devopsschool.com/blog/list-of-top-container-runtime-interface-projects/


What is Container?
---------------------
Container is USER SPACE with 
                    THEIR OWN 
                                NET
                                MNT
                                PMAP
                                with a help of Docker....
                                    Docker takes from KERANL NS.
                            
 47  docker run -d jenkins
   48  docker ps
   49  ps -eaf | grep docker
   50  clear
   51  ps -eaf | grep docker | wc -l
   52  docker run -d jenkins
   53  ps -eaf | grep docker | wc -l
   54  docker run -d jenkins
   55  ps -eaf | grep docker | wc -l
   56  docker ps -a
   57  ps -eaf
   58  id
   59  w
   60  ps -eaf
   61  ps
   62  clear
   63  docker ps -a
   64  docker stop 7ad90b1975be de729d521fb6
   65  docker rm 7ad90b1975be de729d521fb6
   66  docker ps -a
   67  clear
   68  docker ps
   69  docker inspect ebc043157bd6 | grep -i ip
   70  docker inspect 36d1d06fd5a6 | grep -i ip
   71  clear
   72  docker ps
   73  docker exec ebc043157bd6 df -kh
   74  docker exec 36d1d06fd5a6 df -kh
   75  docker ps
   76  clear
   77  docker ps
   78  docker exec ebc043157bd6 ls /var/jenkins_home
   79  docker exec 36d1d06fd5a6 ls /var/jenkins_home
   80  docker exec 36d1d06fd5a6 touch /var/jenkins_home/rajesh.txt
   81  docker exec 36d1d06fd5a6 ls /var/jenkins_home
   82  docker exec ebc043157bd6 ls /var/jenkins_home
   83  clear
   84  docker ps
   85  docker exec ebc043157bd6 ps -eaf
   86  docker exec 36d1d06fd5a6 ps -eaf
   87  history



20 YEARS -----> RUN APP
================================
PHYSICAL MACHINE 
    CPU + RAM + HDD + OS ---> APP
----------------------------------
-- 10 USERS -- 1 APP -- 1 PHYSCIAL 
-- 1000 USERS --- 1 APP --- 10 PHYSICAL MACHINE.
=================================================
            - HIGH AVAILABILILITY
            - SCALIBILYT
            - Security

=======================================================
REDUCE A SOFtWARE RUNNING?
            WASTAGE IN COMPUTING
1 PHYSICAL
        1 CPU   --> 15%---80%%%
        1 RAM
        1 HDD
        1 OSS
-----------------------
2000 PHYSICAL --- 80%
==================================
            VIRUALIZATION

WASTAGE ---- nOT MORE than 15%
==========================================
Demo 
35.154.121.235

How to install docker in RHEL 7.X
====================================
https://www.devopsschool.com/tutorial/docker/install-config/docker-install-commuityedition-centos-rhel.html

Docker----->
        10+

Docker ARCHITECTURE ----
Docker Engine
HUMEN -> DOCKER CLIENT ----REST API----> DOCKER DEAMON --> KERNAL

Working with Containers?
-----------------------
create -> start -> stop -> restart -> pause -> unpause -> stop -> delete
--------------------------------------------------------------------
------RUN--------

  1  clear
    2  sudo yum install -y yum-utils device-mapper-persistent-data lvm2
    3  sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
    4  sudo yum install –y https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
    5  sudo yum-config-manager --enable rhui-REGION-rhel-server-extras
    6  sudo yum install -y docker-ce
    7  clear
    8  which docker
    9  ps -eaf | grep docker
   10  sudo systemctl enable docker
   11  sudo systemctl start docker
   12  ps -eaf | grep docker
   13  which docker
   14  clear
   15  docker pull jenkins
   16  clear
   17  ls
   18  docker images
   19  docker ps
   20  docker ps -a
   21  docker craete jenkins
   22  docker create jenkins
   23  docker ps -a
   24  clear
   25  docker ps -a
   26  docker start d413adb86899
   27  docker ps
   28  history


  9  docker ps
   10  docker run -d jenkins
   11  docker ps
   12  clear
   13  docker ps
   14  clear
   15  ls
   16  clear
   17  docker ps
   18  docker stop feaaed873de5 5d7351244872 d413adb86899
   19  docker ps
   20  docker ps -a
   21  docker rm feaaed873de5 5d7351244872 d413adb86899
   22  clear
   23  docker ps -a
   24  docker stop 48e2210614dd
   25  docker ps -a
   26  docker restart 48e2210614dd
   27  docker ps -a
   28  docker pause 48e2210614dd
   29  docker ps -a
   30  docker upause 48e2210614dd
   31  docker unpause 48e2210614dd
   32  docker ps -a
   33  clear
   34  docker ps -a
   35  docker stop 48e2210614dd
   36  docker rm 48e2210614dd
   37  docker ps
   38  docker ps -a
   39  docker run -d jenkins
   40  docker ps
   41  clear
   42  ls
   43  history


What you want to see inside a container????
========================================
Container --> APP --> Image --> docker hub --> repository --> Docker images.

How to access a container?
    ----------------------
    How to get inside?
            exec - will execute an executables inside a container...
                                with -it and bash - you can interact wtih

            HOW TO SAFTLY EXIT A CONTAINER?
                cONTRL + p  + q
            attach -- Attached to PID 1

    How to access app inside?
            ssh
            http

  90  docker ps
   91  docker exec ebc043157bd6 ls
   92  docker exec ebc043157bd6 df -kh
   93  docker exec ebc043157bd6 fdf
   94  clear
   95  docker ps
   96  docker exec -it ebc043157bd6 /bin/bash
   97  docker ps
   98  docker exec ebc043157bd6 ps -eaf
   99  clear
  100  ls
  101  docker ps
  102  docker attach ebc043157bd6
  103  docker ps
  104  clear
  105  docker ps
  106  ps -eaf
  107  clear
  108  docker ps
  109  docker inspect 36d1d06fd5a6 | grep -i i
  110  docker ps
  111  curl http://172.17.0.4:8080
  112  history

------
Container is RUNNNING COZ OF PID 1 is running.
            PID 1 is running coz of yOU.
            ----------------------------
            You CAN RUN ANYTHING
==============================
Troubleshooting 
                Container
                ------------------
                RUNNING
                --------------
                123  docker logs 36d1d06fd5a6
                124  docker top 36d1d06fd5a6
                -------------------------------
            

                NOT RUNNING
                Docker Image...
                --------------------
                CMD
                ENTRYPOINT




                Docker Engine
                ---------------


Working with Docker Images?
-------------------------
    DOCKER IMAGE IS COMBI OF LAYERS
    LAYERS IS NOTHING BUT FILESYSTEM
    IN CASE OF CONFLICT - TOP LAYER ALWAYS WIN
    ALL LAYERS IS RO
    EXCEPT TOP LAYERS---RW



Sharing Images
-------------------

Kubernetes-Tecnotree-Nov-2019
=============================================
HUMEN
    YAML
        POD
        RC
        DEPLOY
        SVC

Master
    API server - POD -> Container - Image - G Registry
    Clustor Store -Etcd - POD -> Container - Image - G Registry
    Controller manager - POD -> Container - Image - G Registry
    Schedular - POD -> Container - Image - G Registry

ACT LIKE WORKER...
    Kubelet
    Docker
    Kube proxy - POD -> Container - Image - G Registry
Worker
    Kubelet
    docker
    Kube proxy


MASTEr + WORKER - MINIKUBE
-------------------------------
https://github.com/kubernetes/minikube
A VM
    MASTEr
    WORKER
========================================
Cloud using PAAS
==================
AWS - EKS
Azure - AKS
GC - GKE
-----------------
k8s in Cloud but without PAAS
-----------------------------
KOPS
    vmware
    vsph
    aws
    gc
https://github.com/kubernetes/kops

Manual Setup of k8s?
        Soft way
            Using KUBEADM
            https://github.com/kubernetes/kubeadm
        Hard way 
        https://github.com/kelseyhightower/kubernetes-the-hard-way

==================================================================
35.154.143.68
https://www.devopsschool.com/blog/setting-up-kubernetes-clusters-using-kubeadm-manual-way-in-rhel-7-centos7/

======================================
- Download 5 Images.
- Crreate 5 POD - Fill container inside a POD.
- Config each pod to talk to each other.
- Certificate works.
- Config....
----------------------

To start using your cluster, you need to run the following as a regular user:

  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 172.31.26.152:6443 --token 64gd05.ufomemqd9ic01dpx \
    --discovery-token-ca-cert-hash sha256:b7ebb37c6ec4a27f6b525c454d14cf6103657b813354b043741879854713f76d


How to setup work station? -- DONE
=================================

MASTER HEALTH
kubectl cluster-info

VERSION
kubectl version

PODS...
kubectl get pods
kubectl get rc
kubectl get deploy
kubectl get nodes
kubectl get svc
kubectl get ns
=================================================================
Make a Kubernetes healty...
========================


How to setup a worker?
===============================
    Kubelet
    docker
    Kube proxy
    Kubeadm


 40  clear
   41  kubectl get pods --all-namespaces
   42  kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"
   43  kubectl get pods --all-namespaces
   44  kubectl get nodes
   45  clear
   46  sudo -s
   47  kubectl get nodes


WORKER
=============
13.232.166.116
=======================================
How to cleanup
https://www.devopsschool.com/blog/how-to-delete-remove-clean-existing-corrupted-or-old-kubeadm-kubernetes-clusters-setup/

======================================================
=======================================================
How to declare desire in YAML FILE?
-------------------------------------
LIST OF RESOURCES?
        RESOURCE KIND
        V1
            METHOD


https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.16/

API-SERVER/GROUP/POD/v1    
                                    GET
                                    POST
                                    DELETE       
                            alpha
                            ext


   51  clear
   52  kubectl api-resources
   53  clear
   54  kubectl
   55  kubectl   api-versions   Print the supported API versions on the server, in the form of "group/version"
   56  kubectl api-versions
   57  clear
   58  kubectl
   59  kubectl config
   60  clear
   61  kubectl config
   62  kubectl config view
   63  history
==================================================================

Working with NS
------------------------------
Creating a NS
        CMD
        YAML
Explaining a NS FIELD.
Listing a NS
Describing a NS
Editing a NS
Delete a NS

 67  kubectl create
   68  clear
   69  kubectl create ns dev
   70  kubectl get ns
   71  kubectl
   72  kubectl describe ns dev
   73  clear
   74  kubectl describe ns dev
   75  clear
   76  kubectl edit ns dev
   77  clear
   78  kubectl delete ns dev
   79  kubectl get ns
   80  clear
   81  kubectl craete ns qa
   82  kubectl create ns qa
   83  clear
   84  kubectl describe ns qa
   85  kubectl edit ns qa
   86  clear
   87  kubectl
   88  clear
   89  kubectl explain ns
   90  kubectl explain ns.metadata
   91  clear
   92  kubectl explain ns.metadata
   93  kubectl explain ns
   94  kubectl explain ns.spec
   95  clear
   96  history



Working with POD
------------------------------
Creating a POD
        CMD - 
        YAML - 

Explaining a POD FIELD.
Listing a POD
Describing a POD
Editing a POD
Updating a POD
----- USING POD -------
- How to get inside a (Container)
- How to access a POD?
- How to see logs of Containers.

Delete a POD
    CMD
    YAML

pod.yaml
-------------
apiVersion: v1
kind: Pod
metadata:
  name: hello-pod
  labels: 
    app: webserver
spec:
  containers:
  - name: hello-ctr
    image: nginx
    ports:
    - containerPort: 80


  98  kubectl create
   99  clear
  100  kubectl explain pod
  101  c;ear
  102  clear
  103  kubectl explain pod.spec
  104  kubectl explain pod.spec.containers
  105  clear
  106  cf
  107  ls
  108  clear
  109  cd
  110  ls
  111  pwd
  112  vi pod.yaml
  113  kubectl create
  114  clear
  115  kubectl create -f pod.yaml
  116  kubectl get pod
  117  kubectl describe pod hello-pod
  118  clear
  119  ls
  120  kubectl edit pod hello-pod
  121  kubectl describe pod hello-pod
  122  clear
  123  ls
  124* vi
  125  kubectl create -f pod.yaml
  126  kubectl apply -f pod.yaml
  127  kubectl describe pod hello-pod
  128  clear
  129  kubectl apply -f pod.yaml
  130  kubectl apply -f pod.yaml -n=qa
  131  kubectl get pod
  132  kubectl get pod --all-namespaces
  133  clear
  134  kubectl get pod
  135* kubectl delete pod h
  136  kubectl delete pod hello-pod
  137  kubectl delete -f pod.yaml -n=qa
  138  history

143  kubeclt get pod
  144  kubectl get pod
  145  kubectl create -f pod.yaml
  146  kubectl get pod
  147  clear
  148  kubectl get pod
  149  clear
  150  kubectl get pod -o wide
  151  kubectl exec
  152  kubectl help exec
  153  clear
  154  kubectl get pod
  155  kubectl exec -it hello-pod /bin/bash
  156  kubectl attach hello-pod
  157  kubectl get pod
  158  kubectl describe pod hello-pod
  159  clear
  160  ls
  161  kubectl logs hello-pod
  162  kubectl get pod -o wide
  163  curl http://10.44.0.1
  164  kubectl get pod -o wide
  165  kubectl logs hello-pod
  166  curl http://10.44.0.1
  167  kubectl logs hello-pod
  168  curl http://10.44.0.1
  169  kubectl logs hello-pod
  170  kubectl
  171  history







Creating a RC
        CMD - 
        YAML - 

Explaining a RC FIELD.
Listing a RC
Describing a RC
Editing a RC
Updating a RC
----- USING RC -------
Replication
Controller 

Delete a RC
    CMD
    YAML


rc.yaml
===========================
apiVersion: v1
kind: ReplicationController
metadata:
  name: hello-rc
spec:
  replicas: 2   
  template:
    metadata:
      labels:
        app: hello-world
    spec:
      containers:
      - name: hello-ctr
        image: nginx
        ports:
        - containerPort: 80

  175  kubectl create
  176  clear
  177  vi.yaml
  178  vi rc.yaml
  179  kubectl craete -f rc.yaml
  180  kubectl create -f rc.yaml
  181  clear
  182  kubectl get pod
  183  kubectl explain rc
  184  kubectl explain rc.spec
  185  kubectl explain rc.spec.template
  186  kubectl get rc
  187  clear
  188  kubectl get rc
  189  kubectl describe rc hello-rc
  190  clear
  191  ls
  192  kubectl edit rc hello-rc
  193  kubectl get pod
  194  clear
  195  kubectl get pod
  196  vi rc.yaml
  197  kubectl apply -f rc.yaml
  198  kubectl get pod
  199  clear
  200  kubectl get pod
  201  clear
  202  kubectl get pod
  203  clear
  204  kubectl get pod
  205  clear
  206  kubectl get pod
  207  kubectl delete pod hello-rc-65mtc
  208  kubectl get pod
  209  clear
  210  ls
  211  kubectl
  212  clear
  213  kubectl scale
  214  clear
  215  kubectl scale --replicas=20 rc/hello-rc
  216  kubectl get pod
  217  clear
  218  kubectl get pod
  219  clear
  220  kubectl get pod
  221  clear
  222  kubectl get pod
  223  history
==========================================================================
Deployment
--------------------
    RC+ == AKA REplicasets
    rollout
    rollback
    versioned
=========================
Creating a DEPLOYMENT
        CMD - 
        $ kubectl create deployment my-dep --image=nginx
        YAML - 

Explaining a DEPLOYMENT FIELD.
Listing a DEPLOYMENT
Describing a DEPLOYMENT
Editing a DEPLOYMENT
Updating a DEPLOYMENT
----- USING DEPLOYMENT -------
Replication
Controller 

Delete a DEPLOYMENT
    CMD
    YAML

my-dep-6589b6f7dc-blrnm       1/1     Running   0          19m
my-dep-6589b6f7dc-dggrk       1/1     Running   0          19m
my-dep-6589b6f7dc-f9smk       1/1     Running   0          19m
my-dep-6589b6f7dc-g8k9q       1/1     Running   0          19m
my-dep-6589b6f7dc-mztc5

DEPLOY nginx
RS - nginx

Image
scmgalaxy/nginx-devopsschoolv1
scmgalaxy/nginx-devopsschoolv2

 226  kubectl delere rc hello-rc
  227  clear]
  228  kubectl delete rc hello-rc
  229  clear
  230  kubectl get pods
  231  clear
  232  kubectl get pods
  233  clear
  234  kubectl creare
  235  kubectl create
  236  clear
  237  kubectl help create
  238  kubectl help create deployment
  239  clear
  240  kubectl get deploy
  241  kubectl create deployment my-dep --image=nginx
  242  kubectl get deploy
  243  clear
  244  ls
  245  kubectl get deploy
  246  kubectl get pods
  247  kubectl explain deploy
  248  kubectl explain deploy.spec
  249  kubectl explain deploy.spec.template
  250  kubectl explain deploy.spec.template.spec
  251  kubectl explain deploy.spec.template.spec.containers
  252  clear
  253  kubectl get deploy
  254  kubectl describe deploy my-dep
  255  CLEAR
  256  clear
  257  kubectl edit deploy my-dep
  258  kubectl get pods
  259  clear
  260  kubectl get deploy
  261  clear
  262  kubectl
  263  clear
  264  kubectl get
  265  kubectl help get
  266  kubectl get deploy my-dep -o yaml
  267  kubectl help get
  268  kubectl get deploy my-dep -o yaml
  269  kubectl help get
  270  kubectl help get | grep export
  271  kubectl get deploy my-dep -o yaml --export
  272  clear
  273  kubectl get deploy my-dep -o yaml --export
  274  clear
  275  kubectl get deploy my-dep -o yaml --export >> dep.yaml
  276  ls
  277  more dep.yaml
  278  clear
  279  vi dep.yaml
  280  clear
  281  kubectl create -f dep.yaml
  282  kubectl get deploy
  283  clear
  284  kubectl get pods
  285  kubectl describe pod my-jenkins-659c78496f-4xh4p
  286  clear
  287  kubectl get deploy
  288  kubectl get pod
  289  kubectl delete pod my-jenkins-659c78496f-dw6zr
  290  kubectl get pod
  291  clear
  292  kubectl get deploy
  293  kubectl describe deploy my-je
  294  kubectl get rs
  295  clear
  296  ls
  297  kubectl craete -f rc.yaml
  298  vi rc.yaml
  299  kubectl create -f rc.yaml
  300  kubectl get pod
  301  kubectl edit pod hello-rc-2rnc4
  302  kubectl get pod
  303  clear
  304  kubectl get pod
  305  kubectl describe pod hello-rc-2rnc4
  306  kubectl get pod -o wide
  307  curl http://10.44.0.9:8080
  308  clear
  309  ls
  310  clear
  311  ls
  312  kubectl get pod
  313  kubectl edit pod my-dep-6589b6f7dc-mztc5
  314  kubectl get pod
  315  clear
  316  kubectl get pod
  317  clear
  318  kubectl get pod
  319  kubectl get deploy
  320  kubectl describe pod my-dep
  321  clear
  322  kubectl get pod
  323  kubectl describe pod my-dep-6589b6f7dc-blrnm
  324  kubectl get pod
  325  clear
  326  kubectl describe pod my-dep-6589b6f7dc-blrnm
  327  kubectl describe my-dep-6589b6f7dc-dggrk
  328  kubectl describe pod my-dep-6589b6f7dc-dggrk
  329  kubectl describe pod my-dep-6589b6f7dc-f9smk
  330  clear
  331  kubectl get pod
  332  kubectl describe pod my-dep-6589b6f7dc-g8k9q
  333  kubectl describe pod my-dep-6589b6f7dc-mztc5
  334  clear
  335  kubectl get deploy
  336  kubectl edit deploy my-dep
  337  clear
  338*
  339  kubectl get rs
  340  kubectl edit rs my-dep-6589b6f7dc
  341  clear
  342  kubectl get delpy
  343  kubectl get deploy
  344  kubectl describe deploy my-dep
  345  clear
  346  kubectl get pods
  347  clear
  348  ls
  349  history
  350  clear
  351  kubectl get pods
  352  history
  353  clear
  354  ls
  355  kubectl get deploy
  356  kubectl delete deploy my-dep my-jenkins
  357  clear
  358  kubectl get deploy
  359  kubectl get pods
  360  kubectl delete rc hello-rc
  361  clear
  362  kubectl delete pod hellopod
  363  kubectl delete pod hello-pod
  364  clear
  365  kubectl get pod
  366  clear
  367  ls
  368  vi dep.yaml
  369  clear
  370  ls
  371  kubectl apply -f dep.yaml
  372  kubectl get pod -o wide
  373  clear
  374  kubectl get pod -o wide
  375  clear
  376  kubectl get pod -o wide
  377  clear
  378  ls
  379  kubectl get pod -o wide
  380  curl http://10.44.0.2
  381  clear
  382  kubectl
  383  kubectl rollout
  384  kubectl rollout history deploy my-jenkins
  385  cler
  386  vi dep.yaml
  387  clear
  388  kubectl apply -f dep.yaml
  389  kubectl rollout history deploy my-jenkins
  390  kubectl get pod -o wide
  391  clear
  392  kubectl get pod -o wide
  393  curl http://10.44.0.1
  394  curl http://10.44.0.3
  395  kubectl rollout history deploy my-jenkins
  396  curl http://10.44.0.1
  397  kubectl rollout
  398  kubectl rollout undo
  399  history
  400  kubectl help rollout undo
  401  kubectl rollout undo deploy/my-jenkins --to-revision=1
  402  kubectl get pod -o wide
  403  clear
  404  kubectl get pod -o wide
  405  clear
  406  kubectl get pod -o wide
  407  curl http://10.44.0.1
  408  curl http://10.44.0.2
  409  clear
  410  curl http://10.44.0.2
  411  history


WORKING WITH labels
===================================
Apply a label
See a labels
Edit a label
Query a label


kubectl label pods foo unhealthy=true
kubectl label --overwrite pods foo status=unhealthy
kubectl label pods --all status=unhealthy
kubectl label pods foo bar-
reference
https://www.devopsschool.com/blog/working-with-kubernetes-cluster-using-kubectl-part-7-labels/


kubectl label pods my-jenkins-788b58b48-25rh7 name=dbserver
kubectl label --overwrite pods my-jenkins-788b58b48-25rh7 name=jenkinsserver
kubectl label pods --all status=unhealthy
kubectl label pods my-jenkins-788b58b48-25rh7 name-
kubectl label pods --all app-
kubectl delete pod -l status=unhealthy


==================WORKING WITH SVC================================

kubectl label pods --all app-

Create 
    CMD
    yaml

kubectl create service  clusterip svc1 --tcp=8080:80
kubectl label --overwrite pods hello-pod app=svc2
kubectl label --overwrite pods hello-pod1 app=svc2

 500  kubectl create -f pod.yaml
  501  clear
  502  kubectl get pod
  503  kubectl get pod --show-label
  504  kubectl get pod --show-lable
  505  kubectl get pod --show-labels
  506  clear
  507  kubectl get pod --show-labels
  508  clear
  509  kubectl label pods --all app-
  510  kubectl get pod --show-labels
  511  clear
  512  ls
  513  clear
  514  ls
  515  kubectl create
  516  clear
  517  kubectl create service
  518  kubectl create service
  519  clear
  520  kubectl create service  clusterip
  521  kubectl create service  clusterip svc1
  522  kubectl help create service
  523  kubectl help create service clusterip
  524  clear
  525  kubectl get pod
  526  kubectl get pod -o wide
  527  curl http://10.44.0.1
  528  clear
  529  ls
  530  kubectl create service  clusterip svc1 --tcp=8080:80
  531  kubectl get svc
  532  kubectl get svc --show-lables
  533  kubectl get svc --show-labels
  534  clear
  535  kubectl get svc --show-labels
  536  curl http://10.98.191.0
  537  kubectl describe svc svc1
  538  kubectl describe pod hello-pod --show-labels
  539  kubectl describe svc svc1
  540  kubectl get pod hello-pod --show-labels
  541  curl http://10.98.191.0
  542  kubectl label pods hello-pod app=svc1
  543  kubectl get pod hello-pod --show-labels
  544  kubectl describe svc svc1
  545  curl http://10.98.191.0
  546  curl http://10.98.191.0:8080
  547  cp pod.yaml pod1.yaml
  548  vi pod1.yaml
  549  kubectl create -f pod1.yaml
  550  kubectl get pod
  551  kubectl get pod -o wide
  552  curl http://10.44.0.2
  553  curl http://10.44.0.1
  554  clear
  555  ls
  556  kubectl get pod -o wide
  557  kubectl edit pod hello-pod1
  558  kubectl get pod -o wide --show-labels
  559  kubectl get svc
  560  curl http://10.98.191.0
  561  curl http://10.98.191.0:8080
  562  clear
  563  kubectl describe svc svc1
  564  kubectl edit svc svc1
  565  cler
  566  clear
  567  kubectl describe svc svc1
  568  clear
  569  kubectl label pods hello-pod app=svc2
  570  kubectl label --overwrite pods hello-pod app=svc2
  571  kubectl label --overwrite pods hello-pod1 app=svc2
  572  kubectl describe svc svc1
  573  history
  574  clear
  575  kubectget svc
  576  kubect get svc
  577  kubectl get svc
  578  kubect get svc
  579  history


kubectl create service  clusterip svc2 --tcp=8080:80 --tcp=8090:80
kubectl create service nodeport my-ns --tcp=5678:8080



app=my-ns

kubectl label --overwrite pods hello-pod app=my-ns
kubectl label --overwrite pods hello-pod1 app=my-ns

52.66.196.197:30922 
15.206.179.14:30922

427  kubectl create service nodeport my-ns --tcp=5678:8080
  428  kubectl get svc
  429  kubectl get svc --show-lables
  430  kubectl get svc --show-labels
  431  clear
  432  kubectl get svc --show-labels
  433  kubectl edit svc my-ns
  434  kubectl get svc --show-labels
  435  kubectl edit svc my-ns
  436  kubectl get pod
  437  kubectl delete deploy my-jenkins
  438  clear
  439  kubectl get pod
  440  kubectl get pod --show-labels
  441  clear
  442  kubectl label --overwrite pods hello-pod app=my-ns
  443  kubectl label --overwrite pods hello-pod1 app=my-ns
  444  clear
  445  kubectl get pod --show-labels
  446  kubectl edit svc my-ns
  447  clear
  448  ls
  449  kubectl get svc
  450  curl http://10.102.172.232:5678
  451  clear
  452  ls
  453  kubectl get svc



raj-875748690.ap-south-1.elb.amazonaws.com

tectree.k8.rajeshkumar.xyz

kubectl create service loadbalancer my-lbs --tcp=5678:80

  450  curl http://10.102.172.232:5678
  451  clear
  452  ls
  453  kubectl get svc
  454  history
  455  clear
  456  kubectl help create service
  457  kubectl help create service loadbalancer
  458  clear
  459  kubectl create service loadbalancer my-lbs --tcp=5678:80
  460  kubectl get svc
  461  kubectl describe svc my-lbs
  462  history
  463  kubectl create service
  464  history

--------------------------------
POD PROBES
=========================
Readiness
https://www.devopsschool.com/blog/how-to-check-containers-readiness-inside-a-pod-using-readinessprobe/

Liveness
https://www.devopsschool.com/blog/how-to-check-containers-health-inside-a-kubernetes-pod-using-livenessprobe/


Making Node accepting Pods ---- TAINT
https://www.devopsschool.com/blog/working-with-kubernetes-cluster-using-kubectl-part-1/


kubectl taint node ip-172-31-26-152.ap-south-1.compute.internal node-role.kubernetes.io/master:NoSchedule-

\
kubectl delete deploy my-jenkins --grace-period=0 --force --namespace default

kubectl delete pod * --grace-period=0

for p in $(kubectl get pods | grep Terminating | awk '{print $1}'); do kubectl delete pod $p --grace-period=0 --force;done


---------------------------------

Taints
kubectl taint node ip-172-31-7-7.ap-south-1.compute.internal node.kubernetes.io/unreachable:NoSchedule-
kubectl taint node ip-172-31-7-7.ap-south-1.compute.internal nnode.kubernetes.io/unreachable:NoExecute-

kubectl uncordon ip-172-31-7-7.ap-south-1.compute.internal

kubectl patch node ip-172-31-7-7.ap-south-1.compute.internal -p '{"spec":{"Taints":[]}}'

https://stackoverflow.com/questions/35453792/pods-stuck-in-terminating-status
====QA===========
Image of POD(Part of Deployment got changed but PODS still remain same.
externalname Create an ExternalName service.
headless service.


kubectl drain ip-172-31-7-7.ap-south-1.compute.internal --force

kubectl drain ip-172-31-7-7.ap-south-1.compute.internal --ignore-daemonsets --force --delete-local-data

  625  kubectl drain ip-172-31-7-7.ap-south-1.compute.internal --force
  626  kubectl get pod -o wide
  627  kubectl get nodes
  628  kubectl get pod -o wide
  629  clear
  630  ls
  631  kubectl get pod -o wide
  632  clear
  633  kubectl drain ip-172-31-7-7.ap-south-1.compute.internal --ignore-daemonsets --force --delete-local-data


================LAB============================
1. How this work? 
  kubernetes service.
2. Taints
3. drain
4. readiness
5 Liviness
6. 

============================================
Docker and Kubernetes Volume
================================================
TYPES OF VOLUME in DOCKER
    - volume
    - mount
    - memory
    https://www.devopsschool.com/blog/understand-docker-volume-from-beginner-to-deep-dive-level/

 46  clear
   47  docker ps
   48  docker run -it --name=rajesh ubuntu /bin/bash
   49  docker ps -a
   50  docker attach 5b491ead7202
   51  cd /var/lib/docker
   52  clear
   53  ls
   54  cd overlay2/
   55  clear
   56  ls
   57  find . -name rajesh.txt
   58  clear
   59  docker ps -a
   60  docker stop 5b491ead7202
   61  docker rm 5b491ead7202
   62  clear
   63  find . -name rajesh.txt
   64  clear
   65  cd ..
   66  ls
   67  cd volumes
   68  clear
   69  ls
   70  docker volume
   71  docker volume ls
   72  clear
   73  docker volume ls
   74  docker volume craete rajesh
   75  ls
   76  docker volume create rajesh
   77  clear
   78  docker volume ls
   79  ls
   80  cd rajesh/
   81  ls
   82  clear
   83  cd _data/
   84  ls
   85  cd ..
   86  ls
   87  docker run -itd -v rajesh:/opt/rajesh ubuntu /bin/bash
   88  docker attach 1e0e2634c01ddb3490a2266a6dc2dbc4dc000ac16a158d79de2237ce5ce96ac7
   89  docker stop 1e0e2634c01ddb3490a2266a6dc2dbc4dc000ac16a158d79de2237ce5ce96ac7
   90  docker rm1e0e2634c01ddb3490a2266a6dc2dbc4dc000ac16a158d79de2237ce5ce96ac7
   91  docker rm 1e0e2634c01ddb3490a2266a6dc2dbc4dc000ac16a158d79de2237ce5ce96ac7
   92  clear
   93  pwd
   94  ls
   95  cd _data/
   96  ls
   97  clear
   98  ls
   99  docker run -itd -v rajesh:/opt/rajesh ubuntu /bin/bash
  100  docke attach abfd978834f20d9db497c53d9f8a0e469cd41a29de4e36096f28ca0420c4c4a5
  101  docker attach abfd978834f20d9db497c53d9f8a0e469cd41a29de4e36096f28ca0420c4c4a5
  102  clear
  103  docker stop abfd978834f20d9db497c53d9f8a0e469cd41a29de4e36096f28ca0420c4c4a5
  104  docker rm abfd978834f20d9db497c53d9f8a0e469cd41a29de4e36096f28ca0420c4c4a5
  105  clear
  106  ls
  107  cd ..
  108  ls
  109  cd ..
  110  ls
  111  pwd
  112  clear
  113  cd /opt/
  114  ls
  115  mkdir backup
  116  cd backup/
  117  pwd
  118  docker run -it -v /opt/backup:/opt/raju ubuntu
  119  clear
  120  ls
  121  touch file2.txt
  122  ls
  123  docker ps
  124  docker attach 271ffa0638c6
  125  docker stop 271ffa0638c6
  126  docker rm  271ffa0638c6
  127  cd /opt/
  128  ls
  129  cd backup/
  130  ls
  131  history

============================================
1. LMS
2. What would be the next topic

Day 4-
========================
Storage
Networking
Day 5-

EMPTYDIR
==========================================
https://www.devopsschool.com/blog/kubernetes-volume-emptydir-explained-with-examples/

apiVersion: v1
kind: Pod
metadata:
  name: test-pd
spec:
  containers:
  - image: scmgalaxy/nginx-devopsschoolv1
    name: test-container
    volumeMounts:
    - mountPath: /cache
      name: cache-volume
  volumes:
  - name: cache-volume
    emptyDir: {}

==============hostpath==================
https://www.devopsschool.com/blog/kubernetes-volume-hostpath-explained-with-examples/


apiVersion: v1
kind: Pod
metadata:
  name: test-pd
spec:
  containers:
  - image: scmgalaxy/nginx-devopsschoolv1
    name: test-container
    volumeMounts:
    - mountPath: /test-pd
      name: test-volume
  volumes:
  - name: test-volume
    hostPath:
      # directory location on host
      path: /data
      # this field is optional
      type: DirectoryOrCreate

=====================nfs==============================


UBUNTU - 
https://www.devopsschool.com/tutorial/kubernetes/labs/lab-9-kubernetes-configMaps-secrets.html


Setup a NFS server in rhel 7.X
======================
https://www.thegeekdiary.com/centos-rhel-7-configuring-an-nfs-server-and-nfs-client/

 159  yum update
  160  rpm -qa | grep nfs-utils
  161  yum install nfs-utils rpcbind
  162  systemctl enable nfs-server
  163  systemctl enable rpcbind
  164  systemctl enable nfs-lock
  165  systemctl enable nfs-idmap
  166  systemctl start rpcbind
  167  systemctl start nfs-server
  168  systemctl start nfs-lock
  169  systemctl start nfs-idmap
  170  systemctl status nfs
  171  mkdir /tecnotree
  chmod 1777 /tecnotree
  172  vi /etc/exports
        ------------------
        /tecnotree *(rw)

  173  exportfs -r
  174  systemctl restart nfs-server
  showmount -e 
  175  history

-----------client setup-----------
rpm -qa | grep nfs-utils
yum install nfs-utils
mkdir /tmp/mylocal
sudo mount -t nfs -o ro,nosuid 172.31.26.152:/tecnotree /tmp/mylocal
mkdir /tmp/mylocal1
sudo mount -t nfs -o rw,nosuid 172.31.26.152:/tecnotree /tmp/mylocal1
vi /etc/fstab
172.31.26.152:/tecnotree 	/tmp/mylocal	 nfs 	ro,nosuid 	0 	0
172.31.26.152:/tecnotree 	/tmp/mylocal1	 nfs 	rw,nosuid 	0 	0



kind: Pod
apiVersion: v1
metadata:
  name: nfs-in-a-pod
spec:
  containers:
    - name: app
      image: scmgalaxy/nginx-devopsschoolv1
      volumeMounts:
        - name: nfs-volume
          mountPath: /tmp/mylocal1 # Please change the destination you like the share to be mounted too
  volumes:
    - name: nfs-volume
      nfs:
        server: 172.31.26.152 # Please change this to your NFS server
        path: /tecnotree # Please change this to the relevant share


PV and PVC
-------------------
https://www.devopsschool.com/blog/persistentvolume-persistentvolumeclaim-volumes-using-hostpath/

What happens if already used PVC is being used in another pOD?
---

What happens when you use PVC with same spec again with new PV?
[ec2-user@ip-172-31-26-152 ~]$ kubectl get pvc
NAME           STATUS    VOLUME     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvchostpath    Bound     hostpath   1Gi        RWO            manual         8m6s
pvchostpath1   Pending                                        manual         6s
[ec2-user@ip-172-31-26-152 ~]$ kubectl get pv
NAME       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                 STORAGECLASS   REASON   AGE
hostpath   1Gi        RWO            Retain           Bound    default/pvchostpath   manual                  9m59s


kind: Pod
apiVersion: v1
metadata:
  name: task-pv-pod1
spec:
  containers:
    - name: task-pv-container
      image: scmgalaxy/nginx-devopsschoolv1
      ports:
        - containerPort: 80
          name: "http-server"
      volumeMounts:
        - mountPath: "/usr/share/nginx/html"
          name: task-pv-storage
  volumes:
    - name: task-pv-storage
      persistentVolumeClaim:
        claimName: pvchostpath

 972  kubectl create -f pv.yaml
  973  kubectl get pv
  974  clear
  975  ls
  976  kubectl get pvc
  977  vi pvc.yaml
  978  kubectl create -f pvc.yaml
  979  vi pvc.yaml
  980  kubectl create -f pvc.yaml
  981  clear
  982  kubectl get pvc
  983  kubectl get pv
  984  cd /tmp/devopsschool/
  985  ls
  986  vi pvcpod.yaml
  987  kubectl create -f pvcpod.yaml
  988  kubectl get pod
  989  kubectl get pv
  990  kubectl get pvc
  991  kubectl exec -it task-pv-pod /bin/bash
  992  kubectl get pod -o wide
  993  curl http://10.32.0.4
  994  pwd
  995  ls
  996  clear
  997  cd
  998  ls
  999  vi pvcpod2.yaml
 1000  kubectl create -f pvcpod2.yaml
 1001  kubectl get pod
 1002  kubectl get pod -o
 1003  clear
 1004  kubectl get pod -o wide
 1005  curl http://10.32.0.4
 1006  curl http://10.32.0.5
 1007  clear
 1008  ls
 1009  cp pvc.yaml pvc1.yaml
 1010  vi pvc1.yaml
 1011  kubectl create -f pvc1.yaml
 1012  kubectl get pvc
 1013  kubectl get pv
 1014  clear
 1015  ls
 1016  cp pv.yaml pv1.yaml
 1017  cp pv.yaml pv2.yaml
 1018  vi pv1.yaml
 1019  vi pv1.yaml
 1020  vi pv1.yaml
 1021  kubectl create -f pv1.yaml
 1022  kubectl get pv
 1023  clear
 1024  kubectl get pv
 1025  kubectl get pvc
 1026  kubectl get pv
 1027  clear
 1028  kubectl get pv
 1029  kubectl get pvc
 1030  ls
 1031  cp pvc1.yaml pvc2.yaml
 1032  vi pvc2.yaml
 1033  kubectl describe pvc pvchostpath1
 1034  clear
 1035  ls
 1036  kubectl describe pvc
 1037  clear
 1038  kubectl get pv
 1039  kubectl get pvc
 1040  ls
 1041  kubectl create -f pvc2.yaml
 1042  kubectl get pvc
 1043  kubectl get pv
 1044  kubectl get pvc
 1045  kubectl get pv
 1046  kubectl get pvc
 1047  ls
 1048  vi pv.yaml
 1049  kubectl get pv
 1050  vi pv.yaml
 1051  kubectl apply -f pv
 1052  kubectl apply -f pv.yaml
 1053  kubectl get pv
 1054  kubectl get pvc
 1055  ls
 1056  vi pvc.yaml
 1057  kubectl apply -f pvc.yaml
 1058  kubectl apply -f pvc.yaml clear
=======================================
configMaps
====================================
----------
server {
    listen       80;
    server_name  localhost;

    location / {
        proxy_bind 127.0.0.1;
        proxy_pass http://127.0.0.1:3000;
    }

    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }
}
---------------------
kubectl create configmap my-config --from-file=reverseproxy.conf
kubectl get cm
kubectl describe cm my-config

----------------------
apiVersion: v1
kind: Pod
metadata:
  name: helloworld-nginx
  labels:
    app: helloworld-nginx
spec:
  containers:
  - name: nginx
    image: nginx:1.11
    ports:
    - containerPort: 80
    volumeMounts:
    - name: config-volume
      mountPath: /etc/nginx/conf.d
  - name: k8s-demo
    image: wardviaene/k8s-demo
    ports:
    - containerPort: 3000
  volumes:
    - name: config-volume
      configMap:
        name: my-config
        items:
        - key: reverseproxy.conf
          path: myconfo.conf

-------------------------
kubectl exec -it helloworld-nginx /bin/bash
cd /etc/nginx/conf.d

==========================================
secrets
-----------
https://www.devopsschool.com/tutorial/kubernetes/kubernetes-resource-objects/secrets-example-programs.html


apiVersion: v1
kind: Secret
metadata:
  name: mysecret
type: Opaque
data:
  username: YWRtaW4=
  password: MWYyZDFlMmU2N2Rm

apiVersion: v1
kind: Pod
metadata:
  name: mypod
spec:
  containers:
  - name: mypod
    image: scmgalaxy/nginx-devopsschoolv1
    volumeMounts:
    - name: foo
      mountPath: "/etc/foo"
      readOnly: true
  volumes:
  - name: foo
    secret:
      secretName: mysecret


Networking
================================
- bridge
    172.17.0.0/16
        172.17.0.2

br-629951485ae0  - dev
172.18.0.0/16
      172.18.0.2

- host
- none
=============================================================================
=============================================================================
QA
=============================================================================
Authentication and Authorization with K8s.

Authentication
    Certificates

Authorization
    ABAC
    RBAC - Certificates to Authenticate
           Roles to Authorize
================================================
TYPES of USERS
    - NORMAL USERS - 
          using certificates    
          This use has no api resources 
          For humen interaction with API Server         
    - SERVICE ACCOUNT 
          - Secret Tokens
          - This can be created using api resources
          - For KUBERNETES Control plane internal authentication and Auth.

Types of roles on RBAC?
    - Roles
        - Limited to Namespace
        - Humen
        - rules
    - clusterroles
        - Scope to ClustorWIde.
        - Clustor Releated Access.\
            - Can add humen.
        - rules
            apiGroups
            resourceNames
            resources
            verbs
               - create
                - get
                - delete
                - list
                - update
                - edit
                - watch
                - exec


Demo 1 - 
          Create a SERVice ACCOUNT    == ServiceAccount

          Create clusterroles         == ClusterRole
          Add SERVice ACCOUNT into clusterroles = ClusterRoleBinding

kubectl create sa tecnotree-sa
kubectl get sa -A | grep tec

sa.yaml
---------------
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: tecnotree-admin

kubectl create -f sa.yaml
kubectl get sa -A | grep tec
kubectl get secrets





kubectl help create clusterrole
kubectl create clusterrole tecnotree-clusterroles1 --verb=get,list,watch --resource=pods
kubectl get clusterrole
kubectl describe clusterrole tecnotree-clusterroles1

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  namespace: default
  name: tecnotree-clusterroles2
rules:
- apiGroups: ["", "extensions", "apps"]
  resources: ["deployments", "replicasets", "pods"]
  verbs: ["get", "list", "watch", "create", "update", "patch", "delete"] # You can also use ["*"]



kubectl create clusterrolebinding tecnotree-cr-binding --clusterrole=tecnotree-clusterroles2 --user=tecnotree-admin
kubectl get clusterrolebinding
kubectl get clusterrolebinding | grep tec

kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: tecnotree-cr-binding3
subjects:
- kind: ServiceAccount
  name: tecnotree-admin
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: ClusterRole
  name: tecnotree-clusterroles2
  apiGroup: rbac.authorization.k8s.io

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: tecnotree-cr-binding
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: tecnotree-clusterroles2
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: User
  name: tecnotree-admin


=========================
kubectl convert -f pod.yaml
kubectl convert -f pod.yaml --local -o json
kubectl convert -f . | kubectl create -f -


--------------------------------
subjects:
- kind: User
  name: example-user
  apiGroup: rbac.authorization.k8s.io

subjects.kinds CAN BE 
          User
          Group
          ServiceAccount

Demo 2 
          Create a normal Account - NA
          Create a roles = Role
          Add Normal ACCOUNT into roles = RoleBinding


      
======USER At LAPTOP==================
kubectl create namespace office

openssl genrsa -out employee.key 2048

openssl req -new -key employee.key -out employee.csr -subj "/CN=employee/O=bitnami"

======ADMIN AT MASTER using root==================
openssl x509 -req -in employee.csr -CA /etc/kubernetes/pki/ca.crt -CAkey /etc/kubernetes/pki/ca.key -CAcreateserial -out /home/ec2-user/tecnotree/employee.crt -days 500

======USER At LAPTOP==================
kubectl config set-credentials employee --client-certificate=/home/ec2-user/tecnotree/employee.crt  --client-key=/home/ec2-user/tecnotree/employee.key

kubectl config set-context employee-context --cluster=kubernetes --namespace=office --user=employee

kubectl --context=employee-context get pods

==========================================
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  namespace: office
  name: deployment-manager
rules:
- apiGroups: ["", "extensions", "apps"]
  resources: ["deployments", "replicasets", "pods"]
  verbs: ["get", "list", "watch", "create", "update", "patch", "delete"] # You can also use ["*"]

==================================
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: deployment-manager-binding
  namespace: office
subjects:
- kind: User
  name: employee
  apiGroup: ""
roleRef:
  kind: Role
  name: deployment-manager
  apiGroup: ""

============================
$ kubectl --context=employee-context run nginx --image=nginx
$ kubectl --context=employee-context get pods


Statefulsets...
- pod name 
- order
- sticky to pvc
============================
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv0001 
spec:
  capacity:
    storage: 1Gi 
  accessModes:
  - ReadWriteOnce 
  nfs: 
    path: /tecnotree/pv0001
    server: 172.31.14.69 
  persistentVolumeReclaimPolicy: Recycle

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv0002
spec:
  capacity:
    storage: 1Gi 
  accessModes:
  - ReadWriteOnce 
  nfs: 
    path: /tecnotree/pv0002
    server: 172.31.14.69 
  persistentVolumeReclaimPolicy: Recycle

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: k8s.gcr.io/nginx-slim:0.8
        ports:
        - containerPort: 80
          name: web
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 1Gi

apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx


====================HELM=============
https://helm.sh/docs/intro/install/
https://helm.sh/docs/intro/using_helm/


							HELM 3
========================================================================
========================================================================						
=========================================
curl https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3 > get_helm.sh
chmod 700 get_helm.sh
./get_helm.sh
helm version
helm
helm help
------------
Common actions for Helm:

- helm search:    search for charts
- helm pull:      download a chart to your local directory to view
- helm install:   upload the chart to Kubernetes
- helm list:      list releases of charts
-----------------
helm repo add stable https://kubernetes-charts.storage.googleapis.com/
helm search repo stable
helm repo update
helm install stable/mysql --generate-name
helm show chart stable/mysql
helm show all stable/mysql
helm ls
helm list
helm uninstall smiling-penguin
helm rollback
helm get -h


  completion  Generate autocompletions script for the specified shell (bash or zsh)
  create      create a new chart with the given name
  dependency  manage a chart's dependencies
  env         Helm client environment information
  get         download extended information of a named release
  help        Help about any command
  history     fetch release history
  install     install a chart
  lint        examines a chart for possible issues
  list        list releases
  package     package a chart directory into a chart archive
  plugin      install, list, or uninstall Helm plugins
  pull        download a chart from a repository and (optionally) unpack it in local directory
  repo        add, list, remove, update, and index chart repositories
  rollback    roll back a release to a previous revision
  search      search for a keyword in charts
  show        show information of a chart
  status      displays the status of the named release
  template    locally render templates
  test        run tests for a release
  uninstall   uninstall a release
  upgrade     upgrade a release
  verify      verify that a chart at the given path has been signed and is valid
  version     print the client version information







========================
RBAC
Statefulsets
Helm
=

nodes management 
Ingess
Anotations
ETCD and HA

==============================================================================
Compute - 
Storage - 
Networking - 
Security - 

Monitoring
    POD Monitoring
    infra Monitoring using cadvisor-heapster
    http://devopsschool.com/tutorial/kubernetes/kubernetes-pod-container-monitoring-with-cadvisor-heapster.html

    Infra Monitoring
    http://devopsschool.com/tutorial/kubernetes/kubernetes-monitoring-with-prometheus-grafana.html

Logging
    ELK
    http://devopsschool.com/tutorial/kubernetes/kubernetes-monitoring-with-prometheus-grafana.html
    http://devopsschool.com/tutorial/kubernetes/kubernetes-logging-with-elasticsearch-fluentd-kibana.html



Image pull secret
Certificate Manager 
Registry
Scanner
helm repo
encryption
monitoring - 7-8
istio service mesh
discovery
amsbassder



How to reach out to me?
http://rajeshkumar.xyz/


How to find Kubernetes 
        Slides?
        https://www.devopsschool.com/slides
        PDF
        https://www.devopsschool.com/pdf
        Tutorials 
        https://www.devopsschool.com/tutorial/kubernetes/
        Notes - github
        Video
        https://www.youtube.com/channel/UCrXr49kBvXJeQMMl2693c4g
        Blogs
        http://devopsschool.com/blog
        QUIZ
        https://www.devopsschool.com/lms
        LABS
        https://www.devopsschool.com/tutorial/kubernetes/labs/
        Example programs
            https://github.com/devops-school/
            https://github.com/orgs/devopsschool-sample-projects/     




























ERROR
Taints:             node.kubernetes.io/unreachable:NoSchedule

https://stackoverflow.com/questions/56614136/how-to-remove-kube-taints-from-worker-nodes-taints-node-kubernetes-io-unreachab
https://stackoverflow.com/questions/56861796/what-happens-when-you-drain-nodes-in-a-kubernetes-cluster
https://medium.com/@felipedutratine/when-you-try-to-drain-a-kubernetes-node-but-it-blocks-5aba9592d7c9

Kubernetes Access Service located in another namespace

Kubernetes Access Service located in another namespace or Map service to 

Services of type ExternalName map a Service to a DNS name, not to a typical selector such as my-service or cassandra. You specify these Services with the spec.externalName parameter.

This Service definition, for example, maps the my-service Service in the prod namespace to my.database.example.com:

---------Security Policy to send  out in forms of Blog.---------

ExternalName
Services with type ExternalName work as other regular services, but when you want to access to that service name, instead of returning cluster-ip of this service, it returns CNAME record with value that mentioned in externalName:

ExternalName service references to an external DNS address instead of only pods, which will allow
application authors to reference services that exist off platform, on other clusters, or locally.

kubectl create service externalname my-ns --external-name bar.com


====
What about if containers inside a pod is not responding. 
=====
Is there any way if Hostpath is used, next pod must be created in same host.
====
IF PV can be auto scale or increase dynamically?

=====================================================
Can i resize a PV?
- YES

Can i resize a PVC?
- NO, only dynamically provisioned pvc can be resized and the storageclass that provisions the pvc must support resize.

error: persistentvolumeclaims "pvchostpath" could not be patched: persistentvolumeclaims "pvchostpath" is forbidden: only dynamically provisioned pvc can be resized and the storageclass that provisions the pvc must support resize
You can run `kubectl replace -f /tmp/kubectl-edit-2566r.yaml` to try this update again.

How to resize pvc?
if your Workload's Persistent Volume is almost full. How can you expand it? With Kubernetes 1.11 and above, this can now easily be done by just updating the Persistent Volume Claim storage specification.

Only dynamically provisioned pvc can be resized and the storageclass that provisions the pvc must support resize.

Reference
https://dev.to/bzon/resizing-persistent-volumes-in-kubernetes-like-magic-4f96


----
Default secret is jwt token or what?