k8s static podで消せないPodを作る

goforbroke 2021/06/13

Static podをオンプレk8sで試す．

goforbroke 2021/06/13

kubeadmはstatic pod manifestを置く場所が設定されている．

/etc/kubernetes/manifests as the path where kubelet should look for static Pod manifests. Names of static Pod manifests are:
etcd.yaml
kube-apiserver.yaml
kube-controller-manager.yaml
kube-scheduler.yaml

goforbroke 2021/06/13に更新

pod manifestを作成する

$ sudo vim /etc/kubernetes/manifests
apiVersion: v1
kind: Pod
metadata:
  name: static-web
  labels:
    role: myrole
spec:
  containers:
    - name: web
      image: nginx
      ports:
        - name: web
          containerPort: 80
          protocol: TCP

static-web-xxx ができる

% k get pods
NAME              READY   STATUS    RESTARTS   AGE
nginx-rbz55       1/1     Running   2          22d
nginx-vbj84       1/1     Running   1          17d
static-web-k8s1   1/1     Running   0          112m

masterに置かれる

NAME              READY   STATUS    RESTARTS   AGE    IP               NODE   NOMINATED NODE   READINESS GATES
nginx-rbz55       1/1     Running   2          22d    10.244.219.24    k8s3   <none>           <none>
nginx-vbj84       1/1     Running   1          17d    10.244.219.25    k8s3   <none>           <none>
static-web-k8s1   1/1     Running   0          115m   10.244.166.202   k8s1   <none>           <none>

goforbroke 2021/06/13

static pod manifestに，role2: yourrole の変更を加えてみる

apiVersion: v1
kind: Pod
metadata:
  name: static-web
  labels:
    role: myrole
    role2: yourrole
spec:
  containers:
    - name: web
      image: nginx
      ports:
        - name: web
          containerPort: 80
          protocol: TCP

変更を検知してpodが作り直される

% k get po -w
NAME          READY   STATUS    RESTARTS   AGE
nginx-rbz55   1/1     Running   2          22d
nginx-vbj84   1/1     Running   1          17d
static-web-k8s1   0/1     Pending   0          0s
static-web-k8s1   0/1     Pending   0          0s
static-web-k8s1   1/1     Running   0          3s

goforbroke 2021/06/13

稼働中のPodに変更を加えてみる

% kubectl edit po static-web-k8s
# Please edit the object below. Lines beginning with a '#' will be ignored,
# and an empty file will abort the edit. If an error occurs while saving this file will be
# reopened with the relevant failures.
#
apiVersion: v1
kind: Pod
metadata:
  annotations:
....
  labels:
    role: myrole
    role2: minerole

podは作り直されたが，roleはkubectl editで変更されたまま

% k describe po static-web-k8s1
Name:         static-web-k8s1
Namespace:    default
....
Labels:       role=myrole
              role2=minerole

goforbroke 2021/06/13

Static Podを消すと再生成される

% k delete po static-web-k8s1
pod "static-web-k8s1" deleted
% k get po -w
NAME              READY   STATUS    RESTARTS   AGE
nginx-rbz55       1/1     Running   2          22d
nginx-vbj84       1/1     Running   1          17d
static-web-k8s1   0/1     Pending   0          2s
static-web-k8s1   1/1     Running   1          3s

起動したPodはpod manifestの通り生成される．削除直前までの変更は復元されない．

% k describe po static-web-k8s1
Name:         static-web-k8s1
Namespace:    default
...
Labels:       role=myrole
              role2=yourrole