The yaml file is updated to
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: v1.20.0
controllerManager:
extraArgs:
cluster-signing-key-file: /home/k8s/keys/ca.key
bind-address: 0.0.0.0
deployment-controller-sync-period: "50"Also, 1-CPU Unix machine won't be able to run this
error execution phase preflight: [preflight] Some fatal errors occurred:
[ERROR NumCPU]: the number of available CPUs 1 is less than the required 2Complete error log:
root@ubuntu-s-1vcpu-1gb-nyc1-01:~# kubeadm init --config kubeadm-new.yaml
[init] Using Kubernetes version: v1.20.0
[preflight] Running pre-flight checks
[WARNING Service-Docker]: docker service is not enabled, please run 'systemctl enable docker.service'
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[WARNING FileExisting-socat]: socat not found in system path
[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
error execution phase preflight: [preflight] Some fatal errors occurred:
[ERROR NumCPU]: the number of available CPUs 1 is less than the required 2
[ERROR Mem]: the system RAM (985 MB) is less than the minimum 1700 MB
[ERROR FileExisting-conntrack]: conntrack not found in system path
[ERROR KubeletVersion]: couldn't get kubelet version: cannot execute 'kubelet --version': executable file not found in $PATH
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higherMaster node `kubectl describe node kind`
kind get nodes
kind-control-plane
chloe ~ kind get clusters
kind
chloe ~ kubectl describe node kind-control-plane
Name: kind-control-plane
Roles: master
Labels: beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/arch=amd64
kubernetes.io/hostname=kind-control-plane
kubernetes.io/os=linux
node-role.kubernetes.io/master=
Annotations: kubeadm.alpha.kubernetes.io/cri-socket: unix:///run/containerd/containerd.sock
node.alpha.kubernetes.io/ttl: 0
volumes.kubernetes.io/controller-managed-attach-detach: true
CreationTimestamp: Sun, 06 Dec 2020 22:25:55 -0500
Taints: <none>
Unschedulable: false
Lease:
HolderIdentity: kind-control-plane
AcquireTime: <unset>
RenewTime: Mon, 03 May 2021 09:57:54 -0400
Conditions:
Type Status LastHeartbeatTime LastTransitionTime Reason Message
---- ------ ----------------- ------------------ ------ -------
MemoryPressure False Mon, 03 May 2021 09:55:24 -0400 Sun, 18 Apr 2021 23:04:55 -0400 KubeletHasSufficientMemory kubelet has sufficient memory available
DiskPressure False Mon, 03 May 2021 09:55:24 -0400 Sun, 18 Apr 2021 23:04:55 -0400 KubeletHasNoDiskPressure kubelet has no disk pressure
PIDPressure False Mon, 03 May 2021 09:55:24 -0400 Sun, 18 Apr 2021 23:04:55 -0400 KubeletHasSufficientPID kubelet has sufficient PID available
Ready True Mon, 03 May 2021 09:55:24 -0400 Sun, 18 Apr 2021 23:04:55 -0400 KubeletReady kubelet is posting ready status
Addresses:
InternalIP: 172.21.0.2
Hostname: kind-control-plane
Capacity:
cpu: 4
ephemeral-storage: 61255492Ki
hugepages-1Gi: 0
hugepages-2Mi: 0
memory: 2035400Ki
pods: 110
Allocatable:
cpu: 4
ephemeral-storage: 61255492Ki
hugepages-1Gi: 0
hugepages-2Mi: 0
memory: 2035400Ki
pods: 110
System Info:
Machine ID: e4e97c9d87e944e282450378e9a663cd
System UUID: 9e3e327c-ce64-4f4d-bb8a-bffcb37c92bf
Boot ID: 5fadb9b0-00f1-49b1-b73d-abc0769559c1
Kernel Version: 5.10.25-linuxkit
OS Image: Ubuntu Groovy Gorilla (development branch)
Operating System: linux
Architecture: amd64
Container Runtime Version: containerd://1.4.0
Kubelet Version: v1.19.1
Kube-Proxy Version: v1.19.1
PodCIDR: 10.244.0.0/24
PodCIDRs: 10.244.0.0/24
ProviderID: kind://docker/kind/kind-control-plane
Non-terminated Pods: (9 in total)
Namespace Name CPU Requests CPU Limits Memory Requests Memory Limits AGE
--------- ---- ------------ ---------- --------------- ------------- ---
kube-system coredns-f9fd979d6-fkj8x 100m (2%) 0 (0%) 70Mi (3%) 170Mi (8%) 147d
kube-system coredns-f9fd979d6-w27rh 100m (2%) 0 (0%) 70Mi (3%) 170Mi (8%) 147d
kube-system etcd-kind-control-plane 0 (0%) 0 (0%) 0 (0%) 0 (0%) 147d
kube-system kindnet-w8mlw 100m (2%) 100m (2%) 50Mi (2%) 50Mi (2%) 147d
kube-system kube-apiserver-kind-control-plane 250m (6%) 0 (0%) 0 (0%) 0 (0%) 147d
kube-system kube-controller-manager-kind-control-plane 200m (5%) 0 (0%) 0 (0%) 0 (0%) 147d
kube-system kube-proxy-5zlv6 0 (0%) 0 (0%) 0 (0%) 0 (0%) 147d
kube-system kube-scheduler-kind-control-plane 100m (2%) 0 (0%) 0 (0%) 0 (0%) 147d
local-path-storage local-path-provisioner-78776bfc44-28vds 0 (0%) 0 (0%) 0 (0%) 0 (0%) 147d
Allocated resources:
(Total limits may be over 100 percent, i.e., overcommitted.)
Resource Requests Limits
-------- -------- ------
cpu 850m (21%) 100m (2%)
memory 190Mi (9%) 390Mi (19%)
ephemeral-storage 0 (0%) 0 (0%)
hugepages-1Gi 0 (0%) 0 (0%)
hugepages-2Mi 0 (0%) 0 (0%)
Events: <none>
kind create cluster --config=*.yamlkind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
name: local-cluster
# One control plane node and three "workers".
#
# While these will not add more real compute capacity and
# have limited isolation, this can be useful for testing
# rolling updates etc.
#
# The API-server and other control plane components will be
# on the control-plane node.
#
# You probably don't need this unless you are testing Kubernetes itself.
nodes:
- role: control-plane
- role: worker
- role: worker
- role: workerkubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0/aio/deploy/recommended.yamlkubectl apply -f ./RBAC/service-account-admin-user.yaml
kubectl apply -f ./RBAC/cluster-role-binding-admin-user.yaml
kubectl -n kubernetes-dashboard get secret $(kubectl -n kubernetes-dashboard get sa/admin-user -o jsonpath="{.secrets[0].name}") -o go-template="{{.data.token | base64decode}}"
# copy the token
kubectl proxy
# enter the token$ cat ./username.txt
admin
$ cat ./password.txt
c1oudc0w!
$ kubectl create secret generic user --from-file=./username.txt
$ kubectl create secret generic pass --from-file=./password.txtcreate pv and pvc with local-path-storage
$kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-403a048d-ca13-4b46-a614-02c828c49353 128Mi RWO Delete Bound default/local-path-pvc local-path 6m5s
$kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
local-path-pvc Bound pvc-403a048d-ca13-4b46-a614-02c828c49353 128Mi RWO local-path 11mchange headless-service/web-statefulset.yaml file line 22-33 with spec.template.spec.container.volumeMount and spec.volumeClaimTemplates
# can't change stateful on the fly
$k apply -f headless-service/web-statefulset.yaml
The StatefulSet "web" is invalid: spec: Forbidden: updates to statefulset spec for fields other than 'replicas', 'template', and 'updateStrategy' are forbiddendelete statefulset and create again
$k get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
local-path-pvc Bound pvc-403a048d-ca13-4b46-a614-02c828c49353 128Mi RWO local-path 19m
local-path-pvc-web-0 Bound pvc-bacfc1d7-0ff6-407d-869c-184438e140e1 50Mi RWO standard 7s
local-path-pvc-web-1 Bound pvc-61cd15ca-61e2-4042-ab78-1f973711f601 50Mi RWO standard 4s
$k get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-403a048d-ca13-4b46-a614-02c828c49353 128Mi RWO Delete Bound default/local-path-pvc local-path 15m
pvc-61cd15ca-61e2-4042-ab78-1f973711f601 50Mi RWO Delete Bound default/local-path-pvc-web-1 standard 82s
pvc-bacfc1d7-0ff6-407d-869c-184438e140e1 50Mi RWO Delete Bound default/local-path-pvc-web-0 standard 85s
$k get pods
NAME READY STATUS RESTARTS AGE
nginx-deployment-85cf96fb5d-65t8l 1/1 Running 0 26h
nginx-deployment-85cf96fb5d-pv5sl 1/1 Running 0 29h
volume-test 1/1 Running 0 20m
web-0 1/1 Running 0 111s
web-1 1/1 Running 0 108s
$for i in 0 1; do kubectl exec web-$i -- sh -c 'echo hello $(hostname) > /usr/share/nginx/html/index.html'; d
one
$k exec -it web-0 -- /bin/sh
# cat /usr/share/nginx/html/index.html
hello web-0
k apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v0.34.1/deploy/static/provider/kind/deploy.yaml# find out current namespace
kubectl config view --minify | grep namespace
# get all namespaces
k get ns
# change namespace
k config set-context --current --namespace=<new namespce>
# encode string base64
echo 'cGFzc3dvcmQK' | base64
# decode string
echo 'cGFzc3dvcmQK' | base64 -d
# monitoring rolling out status
kubectl rollout status deployment/nginx-deployment
# watch pod creatation `-w`
kubectl get pods -w -l app=<app selector>
# context details
kubectl config --kubeconfig=config-demo view
# context name
kubectl config view -o jsonpath='{.contexts[*].name}' | tr " " "\n"
# check kube context on your local
cat $HOME/.kube/configk config use-context <context name># login on IKS
ibmcloud login -a cloud.ibm.com -r us-south -g default -o chloe.wang1 --sso
# optional command if only one cluster
ibmcloud ks cluster config --cluster c20um43d087iefqf3dr0ic
kubectl config current-context# https://c116-e.us-south.containers.cloud.ibm.com:32336/oauth/token/display
oc login --token=<vQebYtVW....vQsVkos75JQK9vJI_5_eTE> --server=https://c116-e.us-south.containers.cloud.ibm.com:32496
oc project chloe-demo-kind-iks-ocp$ git clone https://github.com/coreos/etcd-operator
$ . example/rbac/create_role.sh
Creating role with ROLE_NAME=etcd-operator, NAMESPACE=default
Warning: rbac.authorization.k8s.io/v1beta1 ClusterRole is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 ClusterRole
clusterrole.rbac.authorization.k8s.io/etcd-operator created
Creating role binding with ROLE_NAME=etcd-operator, ROLE_BINDING_NAME=etcd-operator, NAMESPACE=default
Warning: rbac.authorization.k8s.io/v1beta1 ClusterRoleBinding is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 ClusterRoleBinding
clusterrolebinding.rbac.authorization.k8s.io/etcd-operator created
-bash: POWERLINE_COMMAND_ARGS: unbound variable
Saving session...-bash: HISTTIMEFORMAT: unbound variable
[Process completed]
$ cd ./etcd-operator
$ k create -f ./example/deployment.yaml
$ k get pods
NAME READY STATUS RESTARTS AGE
etcd-operator-646cbffdb6-gwrp4 1/1 Running 0 12s
# once pos is running a CRD is created
$ k get crd
NAME CREATED AT
etcdclusters.etcd.database.coreos.com 2021-05-09T20:28:53Z
$ k apply -f ./example/example-etcd-cluster.yaml
$ k get pods
NAME READY STATUS RESTARTS AGE
etcd-operator-646cbffdb6-gwrp4 1/1 Running 0 2m17s
example-etcd-cluster-5jbbqn56kf 0/1 Running 0 35s
$ k get pods
k get pods
NAME READY STATUS RESTARTS AGE
etcd-operator-646cbffdb6-gwrp4 1/1 Running 0 2m56s
example-etcd-cluster-5jbbqn56kf 1/1 Running 0 74s
example-etcd-cluster-7cvtmc9trc 1/1 Running 0 29s
$ k get pvc data-etcd1-d347a1e3-0 -o yaml > pvc-test.yaml
$ k delete pvc data-etcd1-d347a1e3-0
$ k apply -f etcd-pvc.yaml # with 10Mi and storageclass:local-path
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