檢視 Kubernetes 的原始碼

'''Kubernetes'''是一套由[[Google]]所發展出來的佈署系統。

== 環境 ==

這邊是以Ubuntu 18.04為基礎，在[[AWS]]上使用一台<code>c5.2xlarge</code>與五台<code>r5.large</code>測試。

== 安裝 ==

先安裝[[Docker]]，然後安裝Kubernetes的套件：

<syntaxhighlight lang="bash">
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -; echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list; sudo apt update; sudo apt install -y kubelet kubeadm kubectl
</syntaxhighlight>

== 單機設定 ==
這邊使用[[Calico]]當作網路層：

<syntaxhighlight lang="bash">
sudo kubeadm init --pod-network-cidr=192.168.0.0/16
</syntaxhighlight>

把上面執行結果輸出的命令拿到別台用<code>sudo</code>跑，像是這樣的指令：

<syntaxhighlight lang="bash">
sudo kubeadm join a.b.c.d:6443 --token xxxxxx.xxxxxxxxxxxxxxxx --discovery-token-ca-cert-hash sha256:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
</syntaxhighlight>

接著回到當初跑<code>kubeadm init</code>的機器上，把設定檔放到自己目錄下：

<syntaxhighlight lang="bash">
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
</syntaxhighlight>

接下來啟用Calico設定：

<syntaxhighlight lang="bash">
kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/rbac-kdd.yaml
kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/kubernetes-datastore/calico-networking/1.7/calico.yaml
</syntaxhighlight>

設定好之後不會馬上通，可以用<code>kubectl get nodes --watch</code>可以看到機器會因為retry從<code>NotReady</code>變成<code>Ready</code>。

== HA設定 ==
大多數的設定與單機設定相同，請參考前面對單機版本的說明。

HA版本中需要三台主機跑controller，並且需要透過設定檔設定對應的<code>controlPaneEndpoint</code>與<code>podSubnet</code>（因為<code>--config</code>與<code>--pod-network-cidr</code>不能同時使用）：

<syntaxhighlight lang="yaml">
apiVersion: kubeadm.k8s.io/v1beta1
kind: ClusterConfiguration
kubernetesVersion: stable
apiServer:
  certSANs:
  - "internal-test-gslin-k8s-apiserver-XXXXXXXXXX.us-east-1.elb.amazonaws.com"
controlPlaneEndpoint: "internal-test-gslin-k8s-apiserver-XXXXXXXXXX.us-east-1.elb.amazonaws.com:6443"
networking:
  podSubnet: 192.168.0.0/16
</syntaxhighlight>

然後再透過設定檔初始化cluster：

<syntaxhighlight lang="bash">
sudo kubeadm init --config=kubeadm-config.yaml
</syntaxhighlight>

== 使用所有主機 ==

一開始的主機（master）不會被分配到需求（因為安全因素），透過以下的指令讓master可以分配到需求：

<syntaxhighlight lang="bash">
kubectl taint nodes --all node-role.kubernetes.io/master-
</syntaxhighlight>

== 標籤 ==

可以針對主機進行標籤，供之後的<code>nodeSelector</code>使用：

<syntaxhighlight lang="bash">
kubectl label nodes ip-172-31-1-1 instancetype=c5
kubectl label nodes ip-172-31-1-2 ip-172-31-1-3 ip-172-31-1-4 ip-172-31-1-5 ip-172-31-1-6 instancetype=r5
</syntaxhighlight>

== 範例 ==

<syntaxhighlight lang="yaml">
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: example-r5
spec:
  replicas: 5
  serviceName: example-r5
  selector:
    matchLabels:
      app: example-r5
  template:
    metadata:
      labels:
        app: example-r5
    spec:
      containers:
      - name: example-r5
        image: ubuntu:18.04
        command: ["/bin/sh", "-c"]
        args:
          - export DEBIAN_FRONTEND=noninteractive;
            sed -i 's/archive.ubuntu.com/us.archive.ubuntu.com/' /etc/apt/sources.list;
            apt update;
            apt install -y iproute2 iputils-ping locales mtr-tiny net-tools tzdata wget;
            sleep 3153600000
        resources:
          requests:
            memory: "15Gi"
      nodeSelector:
        instancetype: r5
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: example-c5
spec:
  replicas: 1
  serviceName: example-c5
  selector:
    matchLabels:
      app: example-c5
  template:
    metadata:
      labels:
        app: example-c5
    spec:
      containers:
      - name: example-c5
        image: ubuntu:18.04
        command: ["/bin/sh", "-c"]
        args:
          - export DEBIAN_FRONTEND=noninteractive;
            sed -i 's/archive.ubuntu.com/us.archive.ubuntu.com/' /etc/apt/sources.list;
            apt update;
            apt install -y iproute2 iputils-ping locales mtr-tiny net-tools tzdata wget;
            sleep 3153600000
        resources:
          requests:
            cpu: "7000m"
      nodeSelector:
        instancetype: c5
</syntaxhighlight>

== 相關連結 ==
* [[Docker]]

== 外部連結 ==
* {{Official|https://kubernetes.io/}}
* [https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/ Creating a single master cluster with kubeadm]

[[Category:軟體]]