Closed35

MicroK8sの独習2 〜クラスター内のアプリケーションにアクセスするために外部IPアドレスを公開する〜

流石にkubectl打つのにlxcコマンドから打ってるのだるくなってきたしalias貼ろう

$ alias kubectl='lxc exec mk8s1 -- kubectl'

Deployment情報の確認

kubectl apply -f https://k8s.io/examples/service/load-balancer-example.yaml                                                                                        
deployment.apps/hello-world created
$ kubectl get deployments hello-world
NAME          READY   UP-TO-DATE   AVAILABLE   AGE
hello-world   5/5     5            5           2m24s
$ kubectl describe deployments hello-world
Name:                   hello-world
Namespace:              default
CreationTimestamp:      Mon, 19 Apr 2021 02:24:05 +0000
Labels:                 app.kubernetes.io/name=load-balancer-example
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app.kubernetes.io/name=load-balancer-example
Replicas:               5 desired | 5 updated | 5 total | 5 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  app.kubernetes.io/name=load-balancer-example
  Containers:
   hello-world:
    Image:        gcr.io/google-samples/node-hello:1.0
    Port:         8080/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   hello-world-6df5659cb7 (5/5 replicas created)
Events:
  Type    Reason             Age    From                   Message
  ----    ------             ----   ----                   -------
  Normal  ScalingReplicaSet  3m14s  deployment-controller  Scaled up replica set hello-world-6df5659cb7 to 5

ReplicaSetの確認

$ kubectl get replicasets
NAME                     DESIRED   CURRENT   READY   AGE
hello-world-6df5659cb7   5         5         5       4m46s
$ kubectl describe replicasets
Name:           hello-world-6df5659cb7
Namespace:      default
Selector:       app.kubernetes.io/name=load-balancer-example,pod-template-hash=6df5659cb7
Labels:         app.kubernetes.io/name=load-balancer-example
                pod-template-hash=6df5659cb7
Annotations:    deployment.kubernetes.io/desired-replicas: 5
                deployment.kubernetes.io/max-replicas: 7
                deployment.kubernetes.io/revision: 1
Controlled By:  Deployment/hello-world
Replicas:       5 current / 5 desired
Pods Status:    5 Running / 0 Waiting / 0 Succeeded / 0 Failed
Pod Template:
  Labels:  app.kubernetes.io/name=load-balancer-example
           pod-template-hash=6df5659cb7
  Containers:
   hello-world:
    Image:        gcr.io/google-samples/node-hello:1.0
    Port:         8080/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Events:
  Type    Reason            Age    From                   Message
  ----    ------            ----   ----                   -------
  Normal  SuccessfulCreate  4m52s  replicaset-controller  Created pod: hello-world-6df5659cb7-t4nt2
  Normal  SuccessfulCreate  4m52s  replicaset-controller  Created pod: hello-world-6df5659cb7-mgxvw
  Normal  SuccessfulCreate  4m52s  replicaset-controller  Created pod: hello-world-6df5659cb7-kfzj6
  Normal  SuccessfulCreate  4m52s  replicaset-controller  Created pod: hello-world-6df5659cb7-nkvp2
  Normal  SuccessfulCreate  4m52s  replicaset-controller  Created pod: hello-world-6df5659cb7-gqfvm

これで公開されるはずなんだけど
外部IPアドレスが<pending>のまま変わらない。。。

microk8sじゃだめ?

$ kubectl expose deployment hello-world --type=LoadBalancer --name=my-service
service/my-service exposed
$ kubectl get services my-service
NAME         TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
my-service   LoadBalancer   10.152.183.169   <pending>     8080:30296/TCP   13s

https://www.ntt-tx.co.jp/column/tec/20200904/

microk8sのmetallbアドオンとか言うのを有効化したらいけるみたい
めんどいしmicrok8sコマンドもエイリアスしとこ

$ alias microk8s='lxc exec mk8s1 -- microk8s'
$ microk8s enable metallb
Enabling MetalLB
Enter each IP address range delimited by comma (e.g. '10.64.140.43-10.64.140.49,192.168.0.105-192.168.0.111'): 10.116.214.10-10.116.214.50 
Applying Metallb manifest
namespace/metallb-system created
secret/memberlist created
podsecuritypolicy.policy/controller created
podsecuritypolicy.policy/speaker created
serviceaccount/controller created
serviceaccount/speaker created
clusterrole.rbac.authorization.k8s.io/metallb-system:controller created
clusterrole.rbac.authorization.k8s.io/metallb-system:speaker created
role.rbac.authorization.k8s.io/config-watcher created
role.rbac.authorization.k8s.io/pod-lister created
clusterrolebinding.rbac.authorization.k8s.io/metallb-system:controller created
clusterrolebinding.rbac.authorization.k8s.io/metallb-system:speaker created
rolebinding.rbac.authorization.k8s.io/config-watcher created
rolebinding.rbac.authorization.k8s.io/pod-lister created
daemonset.apps/speaker created
deployment.apps/controller created
configmap/config created
MetalLB is enabled
$ kubectl get service,pod -A
NAMESPACE   NAME                 TYPE           CLUSTER-IP       EXTERNAL-IP     PORT(S)          AGE
default     service/kubernetes   ClusterIP      10.152.183.1     <none>          443/TCP          2d22h
default     service/my-service   LoadBalancer   10.152.183.169   10.116.214.10   8080:30296/TCP   11m

NAMESPACE        NAME                                          READY   STATUS    RESTARTS   AGE
kube-system      pod/calico-kube-controllers-847c8c99d-5tcwh   1/1     Running   0          2d22h
kube-system      pod/calico-node-g6tfl                         1/1     Running   1          2d22h
default          pod/hello-world-6df5659cb7-nkvp2              1/1     Running   0          18m
default          pod/hello-world-6df5659cb7-kfzj6              1/1     Running   0          18m
default          pod/hello-world-6df5659cb7-gqfvm              1/1     Running   0          18m
default          pod/hello-world-6df5659cb7-t4nt2              1/1     Running   0          18m
default          pod/hello-world-6df5659cb7-mgxvw              1/1     Running   0          18m
metallb-system   pod/speaker-5knwj                             1/1     Running   0          2m20s
metallb-system   pod/controller-559b68bfd8-t94sf               1/1     Running   0          2m20s

お、行けた行けた
てかホストOSから簡単にアクセスしようとしてlxcの空いてそうなアドレス帯を勝手に割り当てたけどちゃんとしとかな後で大問題になりそう

$ lxc list
+-------+---------+-----------------------------+----------------------------------------------+-----------+-----------+
| NAME  |  STATE  |            IPV4             |                     IPV6                     |   TYPE    | SNAPSHOTS |
+-------+---------+-----------------------------+----------------------------------------------+-----------+-----------+
| mk8s1 | RUNNING | 10.116.214.130 (eth0)       | fd42:d878:2ae:7d9e:216:3eff:fe7b:6039 (eth0) | CONTAINER | 0         |
|       |         | 10.1.238.128 (vxlan.calico) |                                              |           |           |
+-------+---------+-----------------------------+----------------------------------------------+-----------+-----------+
| mk8s2 | RUNNING | 10.116.214.158 (eth0)       | fd42:d878:2ae:7d9e:216:3eff:fe19:4663 (eth0) | CONTAINER | 0         |
|       |         | 10.1.115.128 (vxlan.calico) |                                              |           |           |
+-------+---------+-----------------------------+----------------------------------------------+-----------+-----------+
$ curl http://10.116.214.10:8080/
Hello Kubernetes!

これクラスタ増やしても単一のIPでバランシングしてくれるってことかな?
てかそうじゃないと前回--type=NodePortでポート公開したときと同じやしな

とりあえず分散確認にもう一台追加するか
しかしmicrok8s joinのコマンド時間かかるけどこれなんかもっと早くする方法ないんか。。。

$ lxc launch mk8s mk8s2 && lxc exec mk8s2 -- microk8s status --wait-ready | head -n4                                                                                                   
Creating mk8s2
Starting mk8s2
microk8s is running
high-availability: no
  datastore master nodes: 127.0.0.1:19001
  datastore standby nodes: none
$ microk8s add-node | tail -n1 | xargs lxc exec mk8s2 --
Contacting cluster at 10.116.214.130
Waiting for this node to finish joining the cluster. ..  
$ kubectl get nodes -o wide
NAME    STATUS   ROLES    AGE     VERSION                     INTERNAL-IP      EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION     CONTAINER-RUNTIME
mk8s1   Ready    <none>   2d22h   v1.20.5-34+40f5951bd9888a   10.116.214.130   <none>        Ubuntu 20.04.2 LTS   5.4.0-71-generic   containerd://1.3.7
mk8s2   Ready    <none>   88s     v1.20.5-34+40f5951bd9888a   10.116.214.251   <none>        Ubuntu 20.04.2 LTS   5.4.0-71-generic   containerd://1.3.7

後は今あるpodsを追加した方にリバランスしたいけどそういうコマンド無いんかな?
とりあえずレプリカセットの数変えて調整するか
てかこれ分散確認するならmicrobotの方が便利よな。。。。

$ kubectl scale --replicas=1 deployment hello-world
deployment.apps/hello-world scaled                                                                                                                                                                              
$ kubectl scale --replicas=5 deployment hello-world                                                                                                                                    
deployment.apps/hello-world scaled
$ kubectl get pods -o wide
NAME                           READY   STATUS              RESTARTS   AGE   IP             NODE    NOMINATED NODE   READINESS GATES
hello-world-6df5659cb7-nkvp2   1/1     Running             0          45m   10.1.238.131   mk8s1   <none>           <none>
hello-world-6df5659cb7-kfzj6   1/1     Terminating         0          45m   10.1.238.132   mk8s1   <none>           <none>
hello-world-6df5659cb7-gqfvm   1/1     Terminating         0          45m   10.1.238.133   mk8s1   <none>           <none>
hello-world-6df5659cb7-t4nt2   1/1     Terminating         0          45m   10.1.238.134   mk8s1   <none>           <none>
hello-world-6df5659cb7-mgxvw   1/1     Terminating         0          45m   10.1.238.135   mk8s1   <none>           <none>
hello-world-6df5659cb7-64vb9   0/1     ContainerCreating   0          3s    <none>         mk8s1   <none>           <none>
hello-world-6df5659cb7-xk5n2   0/1     ContainerCreating   0          3s    <none>         mk8s2   <none>           <none>
hello-world-6df5659cb7-xpdd2   0/1     ContainerCreating   0          3s    <none>         mk8s2   <none>           <none>
hello-world-6df5659cb7-66dcr   0/1     ContainerCreating   0          3s    <none>         mk8s2   <none>           <none>
$ kubectl get pods -o wide
NAME                           READY   STATUS    RESTARTS   AGE     IP             NODE    NOMINATED NODE   READINESS GATES
hello-world-6df5659cb7-nkvp2   1/1     Running   0          47m     10.1.238.131   mk8s1   <none>           <none>
hello-world-6df5659cb7-64vb9   1/1     Running   0          2m18s   10.1.238.137   mk8s1   <none>           <none>
hello-world-6df5659cb7-xk5n2   1/1     Running   0          2m18s   10.1.115.129   mk8s2   <none>           <none>
hello-world-6df5659cb7-xpdd2   1/1     Running   0          2m18s   10.1.115.130   mk8s2   <none>           <none>
hello-world-6df5659cb7-66dcr   1/1     Running   0          2m18s   10.1.115.131   mk8s2   <none>           <none>

一回全部消してmicrobot版でやり直そう

$ kubectl delete services my-service
service "my-service" deleted
$ kubectl delete deployment hello-world

deployment.apps "hello-world" deleted

gistsにmicrobot版作って上げ直して見たから最初からやり直してみよう

$ kubectl apply -f https://git.io/JOzGI
deployment.apps/microbot created
$ kubectl get deployments microbot
NAME       READY   UP-TO-DATE   AVAILABLE   AGE
microbot   5/5     5            5           49s
$ kubectl describe deployments microbot
Name:                   microbot
Namespace:              default
CreationTimestamp:      Mon, 19 Apr 2021 04:21:34 +0000
Labels:                 app.kubernetes.io/name=microbot-load-balancer-example
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app.kubernetes.io/name=microbot-load-balancer-example
Replicas:               5 desired | 5 updated | 5 total | 5 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  app.kubernetes.io/name=microbot-load-balancer-example
  Containers:
   microbot:
    Image:        dontrebootme/microbot:v1
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   microbot-5cd654fccc (5/5 replicas created)
Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  64s   deployment-controller  Scaled up replica set microbot-5cd654fccc to 5
$ kubectl get replicasets
NAME                  DESIRED   CURRENT   READY   AGE
microbot-5cd654fccc   5         5         5       90s
$ kubectl describe replicasets
Name:           microbot-5cd654fccc
Namespace:      default
Selector:       app.kubernetes.io/name=microbot-load-balancer-example,pod-template-hash=5cd654fccc
Labels:         app.kubernetes.io/name=microbot-load-balancer-example
                pod-template-hash=5cd654fccc
Annotations:    deployment.kubernetes.io/desired-replicas: 5
                deployment.kubernetes.io/max-replicas: 7
                deployment.kubernetes.io/revision: 1
Controlled By:  Deployment/microbot
Replicas:       5 current / 5 desired
Pods Status:    5 Running / 0 Waiting / 0 Succeeded / 0 Failed
Pod Template:
  Labels:  app.kubernetes.io/name=microbot-load-balancer-example
           pod-template-hash=5cd654fccc
  Containers:
   microbot:
    Image:        dontrebootme/microbot:v1
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Events:
  Type    Reason            Age   From                   Message
  ----    ------            ----  ----                   -------
  Normal  SuccessfulCreate  97s   replicaset-controller  Created pod: microbot-5cd654fccc-gc2xr
  Normal  SuccessfulCreate  97s   replicaset-controller  Created pod: microbot-5cd654fccc-nvgkt
  Normal  SuccessfulCreate  97s   replicaset-controller  Created pod: microbot-5cd654fccc-4rdxl
  Normal  SuccessfulCreate  97s   replicaset-controller  Created pod: microbot-5cd654fccc-t7tdn
  Normal  SuccessfulCreate  97s   replicaset-controller  Created pod: microbot-5cd654fccc-txjdc

外部IP割り当てて

$ kubectl expose deployment microbot --type=LoadBalancer --name=microbot
service/microbot exposed
$ kubectl get service,pod -A
NAMESPACE   NAME                 TYPE           CLUSTER-IP       EXTERNAL-IP     PORT(S)        AGE
default     service/kubernetes   ClusterIP      10.152.183.1     <none>          443/TCP        2d23h
default     service/microbot     LoadBalancer   10.152.183.249   10.116.214.10   80:32575/TCP   9s

NAMESPACE        NAME                                          READY   STATUS    RESTARTS   AGE
kube-system      pod/calico-kube-controllers-847c8c99d-5tcwh   1/1     Running   0          2d23h
metallb-system   pod/speaker-5knwj                             1/1     Running   0          104m
metallb-system   pod/controller-559b68bfd8-t94sf               1/1     Running   0          104m
kube-system      pod/calico-node-7fhjp                         1/1     Running   0          80m
metallb-system   pod/speaker-tgwp9                             1/1     Running   0          78m
kube-system      pod/calico-node-hdfcp                         1/1     Running   0          78m
default          pod/microbot-5cd654fccc-4rdxl                 1/1     Running   0          2m57s
default          pod/microbot-5cd654fccc-t7tdn                 1/1     Running   0          2m57s
default          pod/microbot-5cd654fccc-gc2xr                 1/1     Running   0          2m57s
default          pod/microbot-5cd654fccc-txjdc                 1/1     Running   0          2m57s
default          pod/microbot-5cd654fccc-nvgkt                 1/1     Running   0          2m57s

ん〜mk8s1に1個しかpod無いのが微妙やなぁ。。。

$ kubectl get pods -o wide
NAME                        READY   STATUS    RESTARTS   AGE     IP             NODE    NOMINATED NODE   READINESS GATES
microbot-5cd654fccc-4rdxl   1/1     Running   0          8m16s   10.1.238.138   mk8s1   <none>           <none>
microbot-5cd654fccc-t7tdn   1/1     Running   0          8m16s   10.1.115.132   mk8s2   <none>           <none>
microbot-5cd654fccc-gc2xr   1/1     Running   0          8m16s   10.1.115.133   mk8s2   <none>           <none>
microbot-5cd654fccc-txjdc   1/1     Running   0          8m16s   10.1.115.134   mk8s2   <none>           <none>
microbot-5cd654fccc-nvgkt   1/1     Running   0          8m16s   10.1.115.135   mk8s2   <none>           <none>

こういう時は経験上レプリカを増減したらええ感じになりそうやな

$ kubectl scale --replicas=2 deployment microbot
deployment.apps/microbot scaled
$ kubectl get pods -o wide
NAME                        READY   STATUS        RESTARTS   AGE     IP             NODE    NOMINATED NODE   READINESS GATES
microbot-5cd654fccc-4rdxl   1/1     Running       0          9m43s   10.1.238.138   mk8s1   <none>           <none>
microbot-5cd654fccc-t7tdn   1/1     Running       0          9m43s   10.1.115.132   mk8s2   <none>           <none>
microbot-5cd654fccc-nvgkt   1/1     Terminating   0          9m43s   10.1.115.135   mk8s2   <none>           <none>
microbot-5cd654fccc-txjdc   1/1     Terminating   0          9m43s   10.1.115.134   mk8s2   <none>           <none>
microbot-5cd654fccc-gc2xr   1/1     Terminating   0          9m43s   10.1.115.133   mk8s2   <none>           <none>
$ kubectl scale --replicas=5 deployment microbot
deployment.apps/microbot scaled
$ kubectl get pods -o wide
NAME                        READY   STATUS    RESTARTS   AGE   IP             NODE    NOMINATED NODE   READINESS GATES
microbot-5cd654fccc-4rdxl   1/1     Running   0          10m   10.1.238.138   mk8s1   <none>           <none>
microbot-5cd654fccc-t7tdn   1/1     Running   0          10m   10.1.115.132   mk8s2   <none>           <none>
microbot-5cd654fccc-4tr69   1/1     Running   0          61s   10.1.115.136   mk8s2   <none>           <none>
microbot-5cd654fccc-992w7   1/1     Running   0          61s   10.1.238.139   mk8s1   <none>           <none>
microbot-5cd654fccc-cj9c6   1/1     Running   0          61s   10.1.238.140   mk8s1   <none>           <none>

2と3やねええ感じ

いい感じ

$ for i in $(seq 100);do w3m -dump http://10.116.214.10/ | grep hostname ; done | sort | uniq -c
     20 Container hostname: microbot-5cd654fccc-4rdxl
     17 Container hostname: microbot-5cd654fccc-4tr69
     15 Container hostname: microbot-5cd654fccc-992w7
     23 Container hostname: microbot-5cd654fccc-cj9c6
     25 Container hostname: microbot-5cd654fccc-t7tdn

とりあえずクラスタを交互に落としてみよか

$ lxc exec mk8s2 -- kubectl get nodes
Error from server (Timeout): the server was unable to return a response in the time allotted, but may still be processing the request (get nodes)

エラー🤣
これはあれかな2台だとHAが無効になってるからってことかな

とりあえずmk8s1を再起動して確認

$ lxc start mk8s1 
$ microk8s status --wait-ready | head -n4
microk8s is running
high-availability: no
  datastore master nodes: 10.116.214.130:19001
  datastore standby nodes: none
$ lxc exec mk8s2 -- kubectl get nodes                                                                                                                                                  
NAME    STATUS   ROLES    AGE   VERSION
mk8s2   Ready    <none>   95m   v1.20.5-34+40f5951bd9888a
mk8s1   Ready    <none>   3d    v1.20.5-34+40f5951bd9888a

マスターノードが1個だけだけどノードとしては2台だから多分HAやね

とりま3台でクラスタ組みますか

$ lxc launch mk8s mk8s3 && lxc exec mk8s3 -- microk8s status --wait-ready | head -n4
Creating mk8s3
Starting mk8s3
microk8s is running
high-availability: no
  datastore master nodes: 127.0.0.1:19001
  datastore standby nodes: none
$ microk8s add-node | tail -n1 | xargs lxc exec mk8s3 --
Contacting cluster at 10.116.214.130
Waiting for this node to finish joining the cluster. ..  
$ microk8s status --wait-ready | head -n4
microk8s is running
high-availability: yes
  datastore master nodes: 10.116.214.130:19001 10.116.214.251:19001 10.116.214.160:19001
  datastore standby nodes: none

うんHA有効になってる

3台にpodを分散しよう

$ kubectl scale --replicas=4 deployment microbot
deployment.apps/microbot scaled
$ kubectl get pods -o wide
NAME                        READY   STATUS        RESTARTS   AGE   IP             NODE    NOMINATED NODE   READINESS GATES
microbot-5cd654fccc-t7tdn   1/1     Running       0          26m   10.1.115.132   mk8s2   <none>           <none>
microbot-5cd654fccc-4tr69   1/1     Running       0          16m   10.1.115.136   mk8s2   <none>           <none>
microbot-5cd654fccc-cj9c6   1/1     Running       1          16m   10.1.238.144   mk8s1   <none>           <none>
microbot-5cd654fccc-4rdxl   1/1     Running       1          26m   10.1.238.145   mk8s1   <none>           <none>
microbot-5cd654fccc-992w7   1/1     Terminating   1          16m   10.1.238.143   mk8s1   <none>           <none>
$ kubectl scale --replicas=6 deployment microbot
deployment.apps/microbot scaled
$ kubectl get pods -o wide
NAME                        READY   STATUS    RESTARTS   AGE   IP             NODE    NOMINATED NODE   READINESS GATES
microbot-5cd654fccc-t7tdn   1/1     Running   0          26m   10.1.115.132   mk8s2   <none>           <none>
microbot-5cd654fccc-4tr69   1/1     Running   0          17m   10.1.115.136   mk8s2   <none>           <none>
microbot-5cd654fccc-cj9c6   1/1     Running   1          17m   10.1.238.144   mk8s1   <none>           <none>
microbot-5cd654fccc-4rdxl   1/1     Running   1          26m   10.1.238.145   mk8s1   <none>           <none>
microbot-5cd654fccc-jwqks   1/1     Running   0          26s   10.1.217.193   mk8s3   <none>           <none>
microbot-5cd654fccc-q52nl   1/1     Running   0          26s   10.1.217.194   mk8s3   <none>           <none>
$ for i in $(seq 100);do w3m -dump http://10.116.214.10/ | grep hostname ; done | sort | uniq -c                                                                                       
     11 Container hostname: microbot-5cd654fccc-4rdxl
     16 Container hostname: microbot-5cd654fccc-4tr69
     16 Container hostname: microbot-5cd654fccc-cj9c6
     19 Container hostname: microbot-5cd654fccc-jwqks
     20 Container hostname: microbot-5cd654fccc-q52nl
     18 Container hostname: microbot-5cd654fccc-t7tdn

いいね2個ずつ分散できた

レプリカの動きなんとなくわかってきたな
減らす時はpodの数が多い(余裕がない?)ところから減らしていって増やす時はpodの数が少ない(余力がある?)ところから増えてく感じかな

気を取り直して1台止めてみよう

$ lxc stop mk8s1
$ lxc exec mk8s2 -- kubectl get nodes
NAME    STATUS     ROLES    AGE    VERSION
mk8s3   Ready      <none>   11m    v1.20.5-34+40f5951bd9888a
mk8s2   Ready      <none>   111m   v1.20.5-34+40f5951bd9888a
mk8s1   NotReady   <none>   3d     v1.20.5-34+40f5951bd9888a
$ lxc exec mk8s2 -- kubectl get pods -o wide
NAME                        READY   STATUS    RESTARTS   AGE     IP             NODE    NOMINATED NODE   READINESS GATES
microbot-5cd654fccc-t7tdn   1/1     Running   0          35m     10.1.115.132   mk8s2   <none>           <none>
microbot-5cd654fccc-4tr69   1/1     Running   0          26m     10.1.115.136   mk8s2   <none>           <none>
microbot-5cd654fccc-jwqks   1/1     Running   0          9m29s   10.1.217.193   mk8s3   <none>           <none>
microbot-5cd654fccc-q52nl   1/1     Running   0          9m29s   10.1.217.194   mk8s3   <none>           <none>
microbot-5cd654fccc-4rdxl   1/1     Running   1          35m     10.1.238.145   mk8s1   <none>           <none>
microbot-5cd654fccc-cj9c6   1/1     Running   1          26m     10.1.238.144   mk8s1   <none>           <none>
$ for i in $(seq 100);do w3m -dump http://10.116.214.10/ | grep hostname ; done | sort | uniq -c
     26 Container hostname: microbot-5cd654fccc-4tr69
     28 Container hostname: microbot-5cd654fccc-jwqks
     19 Container hostname: microbot-5cd654fccc-q52nl
     27 Container hostname: microbot-5cd654fccc-t7tdn

4台しか返ってこないけど一応全部成功はしてるね
前回確認した感じだともっと時間をおいてからなら6台にリバランスされると思うけどとりあえずロードバランサの確認だしそこまでせんでいいか

残り2台も入れ替えで立ち上げてみよう

まずは1⇔2

$ lxc start mk8s1
$ lxc stop mk8s2
$ microk8s status | head -n4
microk8s is running
high-availability: yes
  datastore master nodes: 10.116.214.130:19001 10.116.214.251:19001 10.116.214.160:19001
  datastore standby nodes: none
$ kubectl get nodes
NAME    STATUS     ROLES    AGE    VERSION
mk8s2   NotReady   <none>   119m   v1.20.5-34+40f5951bd9888a
mk8s3   Ready      <none>   20m    v1.20.5-34+40f5951bd9888a
mk8s1   Ready      <none>   3d     v1.20.5-34+40f5951bd9888a
$ kubectl get pods -o wide
NAME                        READY   STATUS        RESTARTS   AGE   IP             NODE    NOMINATED NODE   READINESS GATES
microbot-5cd654fccc-jwqks   1/1     Running       0          17m   10.1.217.193   mk8s3   <none>           <none>
microbot-5cd654fccc-q52nl   1/1     Running       0          17m   10.1.217.194   mk8s3   <none>           <none>
microbot-5cd654fccc-cj9c6   1/1     Running       2          34m   10.1.238.149   mk8s1   <none>           <none>
microbot-5cd654fccc-4rdxl   1/1     Running       2          44m   10.1.238.148   mk8s1   <none>           <none>
microbot-5cd654fccc-4tr69   1/1     Terminating   0          34m   10.1.115.136   mk8s2   <none>           <none>
microbot-5cd654fccc-t7tdn   1/1     Terminating   0          44m   10.1.115.132   mk8s2   <none>           <none>
microbot-5cd654fccc-7mbh9   1/1     Running       0          33s   10.1.217.196   mk8s3   <none>           <none>
microbot-5cd654fccc-54kf4   1/1     Running       0          33s   10.1.217.195   mk8s3   <none>           <none>
$ for i in $(seq 100);do w3m -dump http://10.116.214.10/ | grep hostname ; done | sort | uniq -c
     18 Container hostname: microbot-5cd654fccc-4rdxl
     19 Container hostname: microbot-5cd654fccc-54kf4
     14 Container hostname: microbot-5cd654fccc-7mbh9
     14 Container hostname: microbot-5cd654fccc-cj9c6
     14 Container hostname: microbot-5cd654fccc-jwqks
     21 Container hostname: microbot-5cd654fccc-q52nl

今度はpod6個うまいこと立ち上がり直したな

2⇔3

$ lxc start mk8s2 
$ lxc stop mk8s3 
 kubectl get nodes
Error from server (Timeout): the server was unable to return a response in the time allotted, but may still be processing the request (get nodes)
$ lxc exec mk8s2 -- kubectl get nodes
The connection to the server 127.0.0.1:16443 was refused - did you specify the right host or port?

こわれたっぽい🤔

どうもさっき6台podが立ち上がってるタイミングでクラスタ2台構成に切り替わってHA切れたんじゃないかと予想

とりあえず止めた2を復活させてみたら復旧したっぽい
HA切れたタイミングで2がマスターノードになってたってことかな

$ lxc start mk8s3
$ lxc exec mk8s3 -- microk8s status --wait-ready                                                                                                                                       
microk8s is running                                                                                                                                                                                             
high-availability: yes                                                                                                                                                                                          
  datastore master nodes: 10.116.214.130:19001 10.116.214.251:19001 10.116.214.160:19001
  datastore standby nodes: none

気を取り直して
2⇔3

$ lxc stop mk8s3
$ kubectl get nodes -o wide
NAME    STATUS     ROLES    AGE    VERSION                     INTERNAL-IP      EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION     CONTAINER-RUNTIME
mk8s1   Ready      <none>   3d     v1.20.5-34+40f5951bd9888a   10.116.214.130   <none>        Ubuntu 20.04.2 LTS   5.4.0-71-generic   containerd://1.3.7
mk8s2   Ready      <none>   135m   v1.20.5-34+40f5951bd9888a   10.116.214.251   <none>        Ubuntu 20.04.2 LTS   5.4.0-71-generic   containerd://1.3.7
mk8s3   NotReady   <none>   35m    v1.20.5-34+40f5951bd9888a   10.116.214.160   <none>        Ubuntu 20.04.2 LTS   5.4.0-71-generic   containerd://1.3.7
$ kubectl get pods -o wide
NAME                        READY   STATUS    RESTARTS   AGE   IP             NODE    NOMINATED NODE   READINESS GATES
microbot-5cd654fccc-cj9c6   1/1     Running   2          49m   10.1.238.149   mk8s1   <none>           <none>
microbot-5cd654fccc-4rdxl   1/1     Running   2          59m   10.1.238.148   mk8s1   <none>           <none>
microbot-5cd654fccc-q52nl   1/1     Running   1          33m   10.1.217.197   mk8s3   <none>           <none>
microbot-5cd654fccc-jwqks   1/1     Running   1          33m   10.1.217.199   mk8s3   <none>           <none>
microbot-5cd654fccc-54kf4   1/1     Running   1          16m   10.1.217.198   mk8s3   <none>           <none>
microbot-5cd654fccc-7mbh9   1/1     Running   1          16m   10.1.217.200   mk8s3   <none>           <none>
$ for i in $(seq 100);do w3m -dump http://10.116.214.10/ | grep hostname ; done | sort | uniq -c
     54 Container hostname: microbot-5cd654fccc-4rdxl
     46 Container hostname: microbot-5cd654fccc-cj9c6

う〜ん動いてるんやけど2個しか生きてない。。。

一応どれ落としても同じIPでアクセスできるようにはなってるんだけどなんだか腑に落ちない。。。
HA周りの動きのせいだともうけどこれは多分microk8sの領分でk8sそのものとはまた別の問題かなぁ。。

1台落ちてる状態でもHAのステータス確認すると有効になってるのも不思議だよな
NotReadyってステータス上はなってるのに

起動した直後のノードで
microk8s status --wait-ready
がちゃんと返却された状態なら他のノード落としても大丈夫みたい
ステータス確認も出来ない状態なのに焦って他のノード落とすなってことやな

lxdで払い出すdhcpのレンジ設定できるみたいやな
これでかぶらないように設定しよう

$ lxc network set lxdbr0 ipv4.dhcp.ranges 10.116.214.100-10.116.214.254
$ lxc network show lxdbr0 
config:
  ipv4.address: 10.116.214.1/24
  ipv4.dhcp.ranges: 10.116.214.100-10.116.214.254
  ipv4.nat: "true"
  ipv6.address: fd42:d878:2ae:7d9e::1/64
  ipv6.nat: "true"
description: ""
name: lxdbr0
type: bridge
used_by:
- /1.0/instances/mk8s1
- /1.0/instances/mk8s2
- /1.0/instances/mk8s3
- /1.0/profiles/default
- /1.0/profiles/myDefault
managed: true
status: Created
locations:
- none

metalLBがなんで必要かわからんかったけどAWSとかのサービス使う分にはこれに相当する機能が最初から存在するから自分で準備する必要がないのか

オンプレだとそういうの準備できない場合はこれ使えばええよってことね

でもこれ動いてるどこかのノードが選出されてそこで通信を一手に引き受けるっぽいこと書いてるから
大量アクセスで単一ノードにトラフィックが集中するね

一般的なLBを準備できれば前段に置くだけでAWSとかのそういうのと同じようにtype=LoadBalancer指定するだけで動くように出来るのかな?

とりあえずこの章の書いてる内容は

kubectl expose deployment hello-world --type=LoadBalancer --name=my-service
service/my-service exposed

で適切な外部LBがある環境ならデプロイしたアプリを外部に出せるよって感じかな

また大したことしてないのに長大になってきてしまったとりあえずなんとなくわかったし一旦閉じよう

このスクラップは2021/04/19にクローズされました
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