Kubernetes
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c5.2xlarge與五台r5.large測試。
安裝
先安裝Docker，然後安裝Kubernetes的套件：
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
設定
這邊使用Calico當作網絡層：
sudo kubeadm init --pod-network-cidr=192.168.0.0/16
把上面執行結果輸出的命令拿到別台用sudo跑，像是這樣的指令：
sudo kubeadm join a.b.c.d:6443 --token xxxxxx.xxxxxxxxxxxxxxxx --discovery-token-ca-cert-hash sha256:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
接着回到當初跑kubeadm init的機器上，把設定檔放到自己目錄下：
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
接下來啟用Calico設定：
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
設定好之後不會馬上通，可以用kubectl get nodes --watch可以看到機器會因為retry從NotReady變成Ready。
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：
kubectl taint nodes --all node-role.kubernetes.io/master-
標籤
可以針對主機進行標籤，供之後的nodeSelector使用：
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
範例
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