microk8sを用いると簡単に単ノード構成のkubernetesを構築することができ、さらにkubernetesクラスタも構築することができるようなので試してみることにしました。
インストールの手順は、microk8sを踏襲することにします。
Install MicroK8s on Linux
sudo snap install microk8s --classicユーザを micro8ksのグループへ追加（次のログイン時に反映される）
sudo usermod -a -G microk8s $USER
sudo chown -f -R $USER ~/.kubemicrok8s起動状況の表示
$ microk8s status
microk8s is running
high-availability: yes
datastore master nodes: 192.168.68.132:19001 192.168.68.129:19001 192.168.68.111:19001
datastore standby nodes: 192.168.68.130:19001
addons:
enabled:
dashboard # The Kubernetes dashboard
dns # CoreDNS
ha-cluster # Configure high availability on the current node
ingress # Ingress controller for external access
metallb # Loadbalancer for your Kubernetes cluster
metrics-server # K8s Metrics Server for API access to service metrics
storage # Storage class; allocates storage from host directory
disabled:
ambassador # Ambassador API Gateway and Ingress
cilium # SDN, fast with full network policy
fluentd # Elasticsearch-Fluentd-Kibana logging and monitoring
gpu # Automatic enablement of Nvidia CUDA
helm # Helm 2 - the package manager for Kubernetes
helm3 # Helm 3 - Kubernetes package manager
host-access # Allow Pods connecting to Host services smoothly
istio # Core Istio service mesh services
jaeger # Kubernetes Jaeger operator with its simple config
keda # Kubernetes-based Event Driven Autoscaling
knative # The Knative framework on Kubernetes.
kubeflow # Kubeflow for easy ML deployments
linkerd # Linkerd is a service mesh for Kubernetes and other frameworks
multus # Multus CNI enables attaching multiple network interfaces to pods
portainer # Portainer UI for your Kubernetes cluster
prometheus # Prometheus operator for monitoring and logging
rbac # Role-Based Access Control for authorisation
registry # Private image registry exposed on localhost:32000
traefik # traefik Ingress controller for external accessCheck the status while Kubernetes starts
microk8s status --wait-readydisableされている中から必要なservices を有効化
microk8s enable dashboard dns registry istioここで microk8s enable –help を実行すると利用可能なサービスを一覧できます。
起動中の利用可能なサービスを表示
microk8s kubectl get all --all-namespaces$ microk8s kubectl get all --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
ingress pod/nginx-ingress-microk8s-controller-rj2vj 1/1 Running 0 22h
metallb-system pod/speaker-bwpl7 1/1 Running 0 22h
metallb-system pod/speaker-g2kcl 1/1 Running 1 22h
ingress pod/nginx-ingress-microk8s-controller-dvb29 1/1 Running 1 22h
kube-system pod/calico-node-jdpsl 1/1 Running 1 23h
kube-system pod/hostpath-provisioner-5c65fbdb4f-wlg45 1/1 Terminating 1 22h
kube-system pod/coredns-86f78bb79c-r94k8 1/1 Terminating 1 23h
kube-system pod/hostpath-provisioner-5c65fbdb4f-6hz6n 1/1 Running 0 10h
kube-system pod/calico-node-8hqxv 1/1 Running 0 24h
ingress pod/nginx-ingress-microk8s-controller-w5qv9 1/1 Running 0 22h
metallb-system pod/speaker-wpg4z 1/1 Running 0 22h
kube-system pod/coredns-86f78bb79c-hl56s 1/1 Terminating 0 10h
metallb-system pod/controller-559b68bfd8-6nw4k 1/1 Running 0 10h
metallb-system pod/speaker-nrw9w 1/1 Running 17 22h
kube-system pod/coredns-86f78bb79c-72zp4 1/1 Running 3 10h
kube-system pod/calico-node-nk45x 1/1 Running 18 24h
ingress pod/nginx-ingress-microk8s-controller-cnpzq 1/1 Running 15 22h
kube-system pod/metrics-server-8bbfb4bdb-9kh97 1/1 Running 0 38m
kube-system pod/dashboard-metrics-scraper-6c4568dc68-vrmzl 1/1 Running 0 36m
kube-system pod/calico-kube-controllers-847c8c99d-z867h 1/1 Running 0 33h
kube-system pod/calico-node-ppczw 1/1 Running 0 24h
kube-system pod/kubernetes-dashboard-7ffd448895-q7zkf 1/1 Running 7 36m
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default service/kubernetes ClusterIP 10.152.183.1 <none> 443/TCP 33h
kube-system service/kube-dns ClusterIP 10.152.183.10 <none> 53/UDP,53/TCP,9153/TCP 23h
kube-system service/metrics-server ClusterIP 10.152.183.231 <none> 443/TCP 38m
kube-system service/kubernetes-dashboard ClusterIP 10.152.183.118 <none> 443/TCP 36m
kube-system service/dashboard-metrics-scraper ClusterIP 10.152.183.83 <none> 8000/TCP 36m
NAMESPACE NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE
kube-system daemonset.apps/calico-node 4 4 2 4 2 kubernetes.io/os=linux 33h
metallb-system daemonset.apps/speaker 2 2 2 2 2 beta.kubernetes.io/os=linux 22h
ingress daemonset.apps/nginx-ingress-microk8s-controller 2 2 2 2 2 <none> 22h
NAMESPACE NAME READY UP-TO-DATE AVAILABLE AGE
kube-system deployment.apps/hostpath-provisioner 1/1 1 1 22h
metallb-system deployment.apps/controller 1/1 1 1 22h
kube-system deployment.apps/calico-kube-controllers 1/1 1 1 33h
kube-system deployment.apps/coredns 1/1 1 1 23h
kube-system deployment.apps/metrics-server 1/1 1 1 38m
kube-system deployment.apps/dashboard-metrics-scraper 1/1 1 1 36m
kube-system deployment.apps/kubernetes-dashboard 1/1 1 1 36m
NAMESPACE NAME DESIRED CURRENT READY AGE
kube-system replicaset.apps/hostpath-provisioner-5c65fbdb4f 1 1 1 22h
metallb-system replicaset.apps/controller-559b68bfd8 1 1 1 22h
kube-system replicaset.apps/calico-kube-controllers-847c8c99d 1 1 1 33h
kube-system replicaset.apps/coredns-86f78bb79c 1 1 1 23h
kube-system replicaset.apps/metrics-server-8bbfb4bdb 1 1 1 38m
kube-system replicaset.apps/dashboard-metrics-scraper-6c4568dc68 1 1 1 36m
kube-system replicaset.apps/kubernetes-dashboard-7ffd448895 1 1 1 36mKubernetesの起動と停止
microk8s start
or
microk8s stopノードをクラスターへ追加；microk8s joink～ の行をCopyし、追加するノードの端末へPasteして実行する。
microk8s add-node
/* ノード参加に必要な以下のようなメッセージ が表示されるので、参加するノードで、microk8s joinjoinを実行 */
Join node with:
microk8s join ip-172-31-20-243:25000/DDOkUupkmaBezNnMheTBqFYHLWINGDbf
If the node you are adding is not reachable through the default
interface you can use one of the following:
microk8s join 10.1.84.0:25000/DDOkUupkmaBezNnMheTBqFYHLWINGDbf
microk8s join 10.22.254.77:25000/DDOkUupkmaBezNnMheTBqFYHLWINGDbf- 参加しているノードの表示
microk8s kubectl get nofrirewallの設定
sudo ufw allow in on cni0 && sudo ufw allow out on cni0
sudo ufw default allow routeddashboardの利用するには、アクセスのためのトークンを作成します。
token=$(microk8s kubectl -n kube-system get secret | grep default-token | cut -d " " -f1)
microk8s kubectl -n kube-system describe secret $tokenトークンの一例（dashboardをアクセスした際に要求されるtoken。Copy&Pasteでログイン）
Name: default-token-57rfp
Namespace: kube-system
Labels: <none>
Annotations: kubernetes.io/service-account.name: default
kubernetes.io/service-account.uid: 2f782a0f-3d04-43aa-88fe-a6d67364b297
Type: kubernetes.io/service-account-token
Data
====
namespace: 11 bytes
token: eyJhbGciOiJSUzI1NiIsImtpZCI6Im56Vm1vTVJyaXVJQzBaSnM4SS1PTWNrZTkzMlJMdFBqS0NMeFgxWnIzdWMifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJkZWZhdWx0LXRva2VuLTU3cmZwIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6ImRlZmF1bHQiLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlcnZpY2UtYWNjb3VudC51aWQiOiIyZjc4MmEwZi0zZDA0LTQzYWEtODhmZS1hNmQ2NzM2NGIyOTciLCJzdWIiOiJzeXN0ZW06c2VydmljZWFjY291bnQ6a3ViZS1zeXN0ZW06ZGVmYXVsdCJ9.EGkufnRoGONpt14vmBLAG8vF2khLtHZLx8J0VNzJUxX28z8NtSNB5MhRKCamChqXdTRm1iwyaPQIlgWwaKTci7CA9TNf8o70EmJBOO1AvDJ_QcC2mRpQzrkxcl0wiuLbpkHzC-wvuzqwY4b32utYikbUxHNjiDsOSyVmqN9NyDZ84FKRZUGkaWrgJmUNakBGetqaOPSpTAIC8JncPznYIOt88nyx6kCIrOFJjjh_UhPGMfevVNFZcji617uNTencBVrkwaej6O09wyqzjPVK-jWXhHaigaIb5O2TmjfcQJCyiEkF_6LYFGr7ilOzzpbAqw-iICmBQUW1Mred3FsN9Q
ca.crt: 1103 bytes
dashboardへログインした画面
dashboardでノードの状態を表示
podの追加例：
インストールの過程で気になったキーワード
３ノード以上の構成では、データストアーがクラスター内で複製され、１ノード故障に対しては耐性がある。
From the 1.19 release of MicroK8s, HA is enabled by default. If your cluster consists of three or more nodes, the datastore will be replicated across the nodes and it will be resilient to a single failure (if one node develops a problem, workloads will continue to run without interruption).