架构►container►k8s

k8s problems

Pod 无法解析域名

Pod DNS 策略模式是 ClusterFirst，系统 /etc/resolve.conf 内容如下。

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nameserver 127.0.0.53
options edns0 trust-ad
search .

导致 Pod 里面的 /etc/resolv.conf 配置也是如此，无法正常解析域名。先删除 /etc/resolv.conf（/run/systemd/resolve/stub-resolv.conf 的软链） ，再创建并写入如下内容。

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nameserver 223.5.5.5
nameserver 8.8.8.8
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sudo rm /etc/resolv.conf
sudo vim /etc/resolv.conf

重启 Pods。

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kubectl delete pods --all -n=<namespace> # 删除所有 pods

pod didn’t trigger scale-up

错误信息

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.. (combined from similar events): pod didn't trigger scale-up (it wouldn't fit if a new node is added): 2 Insufficient memory, 7 can't increase node group size

原因

  • pod 添加的 container 的内存、CPU 资源超过资源池机器的限制，导致无法扩容

解决

  • 减少 container 的 memory / cpu

Core Dump 及保存

设置 core dump 保存路径及命名

在 deployment.yaml 中配置，运行命令 echo "core.%p" > /proc/sys/kernel/core_pattern 。

映射 HostPath，容器重启不删除文件。

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# deployment.yaml
spec:
	template:
		spec:
			volumes:
				- name: core-dump-volume
          hostPath:
            path: /data/core
            type: DirectoryOrCreate
			containers:
				- name: {container-name}
					volumeMounts:
						- name: core-dump-volume
							mountPath: /data/core
python►notes

install python from source

从源码安装 Python3

设置版本

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export PYTHON_VERSION=3.9.13
export PYTHON_MAJOR=3

下载

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wget https://www.python.org/ftp/python/${PYTHON_VERSION}/Python-${PYTHON_VERSION}.tgz
tar -xvzf Python-${PYTHON_VERSION}.tgz --no-check-certificate
cd Python-${PYTHON_VERSION}

配置

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./configure \
    --prefix=/opt/python/${PYTHON_VERSION} \
    --enable-shared \
    --enable-ipv6 \
    LDFLAGS=-Wl,-rpath=/opt/python/${PYTHON_VERSION}/lib,--disable-new-dtags \
    --enable-optimizations

编译安装

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make
sudo make install

安装 pip

安装 python 3.9.13 时已安装 pip

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curl -O https://bootstrap.pypa.io/get-pip.py
sudo /opt/python/${PYTHON_VERSION}/bin/python${PYTHON_MAJOR} get-pip.py

使用安装命令

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# ubuntu
apt install python-pip	#python 2
apt install python3-pip	#python 3

# centos
yum install epel-release 
yum install python-pip
# 或
dnf install python-pip	#Python 2
dnf install python3		#Python 3
架构►container►k8s►k9s

k9s setup

Install

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# brew
brew install derailed/k9s/k9s

# snap
sudo snap install k9s

连接集群

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# microk8s
# 保存内容至 ~/.kube/config 
# k9s 会读取配置并连接集群
microk8s config > ~/.kube/config
play►network

network

设置网关导致端口网关失效

参考这里。

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ip route add 192.168.6.0/24 dev br0 table 16
ip route add default via 192.168.6.1 dev br0 table 16
ip rule iif to ipproto tcp sport 10014 lookup 16

另外一种方式。

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ip route add 192.168.6.0/24 dev br0 table 10
ip route add default via 192.168.6.1 table 10
ip route add 192.168.9.0/24 dev br1 table 12
ip route add default via 192.168.9.1 table 12
ip rule add from 192.168.6.0/24 table 10 priority 1
ip rule add from 192.168.9.0/24 table 12 priority 2

# 添加 docker 网络
ip route add 172.17.0.0/16 dev docker0 table 10
ip route add 172.17.0.0/16 dev docker0 table 12

# 刷新配置
ip route flush cache

# 校验
$ ip route show table 12
default via 192.168.9.1 dev br1
172.17.0.0/16 dev docker0 scope link
192.168.9.0/24 dev br1 scope link

示例

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# out
ip route add default via 192.168.6.1 dev ens8 table 10
ip route add default via 192.168.9.1 dev ens9 table 12
# in
ip rule add from 192.168.6.0/24 table 10 priority 1
ip rule add from 192.168.9.0/24 table 12 priority 2 # 可以不设置 priority

# 如果有设置了默认的路由，可以忽略其中的一个，比如有如下默认路由
ip route add default via 192.168.6.1 dev ens8
# 那么只需要设置 192.168.9.0/24
# ip route add default via 192.168.9.1 dev ens9 table 12
ip route add 192.168.9.0/24 dev ens9 proto kernel scope link src 192.168.9.8 
ip rule add from 192.168.9.0/24 table 12

连接路由器的 VPN 之后无法访问内网服务

原因

路由器局域网网段和外网网段冲突，导致访问局域网 ip 不走 vpn 网络。

设置

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# macos, route 命令
## 查看路由表
sudo netstat -rn
192.168.6.6        link#6             UHRLWIi           en0      8   
## en0 是 wifi 网络接口, vpn 的网络端口是 utun3
## 修改路由, 把 192.168.6.0/24 所有网段的路由走 vpn
sudo route change 192.168.6.0/24 -interface utun3

USB 外接网卡

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$ lshw -c network
WARNING: you should run this program as super-user.
  *-network
       ...
       logical name: enp0s31f6
       ...
  *-network DISABLED
       ...
       logical name: enxf8e43b1a1229
       ...
play►pve

pve - usage

直通

硬盘直通

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# sata 硬盘直通
qm set {vm-id} -sata0 /dev/disk/by-id/{disk-id}
# 示例
qm set 105 -sata0 /dev/disk/by-id/ata-HS-SSD-A260_1024G_30066931838
play►samb

samba server

安装

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# ubuntu
sudo apt update
sudo apt install samba

配置

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sudo vim /etc/samba/smb.conf
# 在文档最后添加
[sambashare]
    comment = Samba on Ubuntu
    path = /home/username/sambashare
    read only = no
    browsable = yes

重启服务

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sudo service smbd restart

添加用户并设置密码

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sudo smbpasswd -a <username>
架构►container►microk8s

microk8s usage

描述

参考 官方文档，搭建一个三节点 k8s 集群。

节点 ip
k8s01-1 10.1.0.78
k8s01-2 10.1.0.62
k8s01-3 10.1.0.242

alias

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# ~/.bash_aliases
alias k='microk8s kubectl'
alias mk='microk8s'

# 或者 ~/.local/bin/kubectl, 适配 k9s
#!/bin/bash
exec microk8s.kubectl $(echo "$*" | sed 's/-- sh.*/sh/')

加入用户组

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sudo usermod -a -G microk8s $USER
sudo chown -f -R $USER ~/.kube
# 重新进入 session
su - $USER

Hosts

所有节点

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10.1.0.78 k8s01-1
10.1.0.62 k8s01-2
10.1.0.242 k8s01-3

初始化集群

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# k8s01-1 主节点
$ mk add-node
From the node you wish to join to this cluster, run the following:
microk8s join 192.168.9.103:25000/5b502d061dd31ec58d1f6ddf96e10c56/be841c6899a7

Use the '--worker' flag to join a node as a worker not running the control plane, eg:
microk8s join 10.1.0.78:25000/5b502d061dd31ec58d1f6ddf96e10c56/be841c6899a7 --worker

If the node you are adding is not reachable through the default interface you can use one of the following:
microk8s join 10.1.0.78:25000/5b502d061dd31ec58d1f6ddf96e10c56/be841c6899a7

# k8s01-2 worker 节点
microk8s join 10.1.0.78:25000/5b502d061dd31ec58d1f6ddf96e10c56/be841c6899a7 --worker

# 对 k8s01-3, 重复上述操作

查看状态

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$ k get nodes
NAME      STATUS   ROLES    AGE     VERSION
k8s01-1   Ready    <none>   2d12h   v1.24.3-2+63243a96d1c393
k8s01-2   Ready    <none>   77s     v1.24.3-2+63243a96d1c393
k8s01-3   Ready    <none>   64s     v1.24.3-2+63243a96d1c393

更详细的状态

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$ k get node -o wide
NAME      STATUS   ROLES    AGE     VERSION                    INTERNAL-IP   EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION      CONTAINER-RUNTIME
k8s01-1   Ready    <none>   2d12h   v1.24.3-2+63243a96d1c393   10.1.0.78     <none>        Ubuntu 20.04.4 LTS   5.4.0-124-generic   containerd://1.5.13
k8s01-2   Ready    <none>   5m23s   v1.24.3-2+63243a96d1c393   10.1.0.62     <none>        Ubuntu 20.04.4 LTS   5.4.0-124-generic   containerd://1.5.13
k8s01-3   Ready    <none>   5m10s   v1.24.3-2+63243a96d1c393   10.1.0.242    <none>        Ubuntu 20.04.4 LTS   5.4.0-124-generic   containerd://1.5.13

安装插件

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# 主节点
mk enable dns storage dashboard helm3

获取 k8s 配置

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mkdir ~/.kube
mk config > ~/.kube/config

问题排查

查看事件

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k get events --sort-by=.metadata.creationTimestamp --namespace=kube-system

异常

Failed create pod sandbox

错误信息

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Failed create pod sandbox: rpc error: code = Unknown desc = failed to set up sandbox container ... error getting ClusterInformation: Get ... https://10.152.183.1:443 ...

原因

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NAMESPACE↑                 NAME                      TYPE                     CLUSTER-IP     
default                    kubernetes                ClusterIP                10.152.183.1

错误信息提示请求 ClusterIP 异常，检查节点 IP。

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$ k get nodes -o wide
NAME STATUS   ROLES    AGE   VERSION   INTERNAL-IP   ... KERNEL-VERSION      CONTAINER-RUNTIME
a    Ready    <none>   16h   v1.27.2   172.21.0.3    ... 5.4.0-126-generic   containerd://1.6.15
b    Ready    <none>   16h   v1.27.2   192.168.6.201 ... 5.15.0-76-generic   containerd://1.6.15

解决
在 b 节点无法通过 a 的 INTERNAL-IP 访问 a（controller） 节点，修改两个节点的 --node-ip 为可以访问的 ip。

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microk8s stop
# or for workers: sudo snap stop microk8s

sudo vim.tiny /var/snap/microk8s/current/args/kubelet
# Add this to bottom: --node-ip=<this-specific-node-lan-ip>

sudo vim.tiny /var/snap/microk8s/current/args/kube-apiserver
# Add this to bottom: --advertise-address=<this-specific-node-lan-ip>

microk8s start
# or for workers: sudo snap start microk8s

certificate is valid for kubernetes … not for mydomain.com

参考 这里。

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$ vim /var/snap/microk8s/current/certs/csr.conf.template
# 添加域名
[ alt_names ]
DNS.1 = kubernetes
DNS.2 = kubernetes.default
DNS.3 = kubernetes.default.svc
DNS.4 = kubernetes.default.svc.cluster
DNS.5 = kubernetes.default.svc.cluster.local
DNS.6 = mydomain.com  # 添加一行

# 生效
$ sudo microk8s refresh-certs --cert server.crt
架构►container►microk8s

microk8s 安装

文档

安装

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sudo snap install microk8s --classic

加入用户组

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sudo usermod -a -G microk8s $USER
sudo chown -f -R $USER ~/.kube
# 重新进入 session
su - $USER

配置 k8s.gcr.io 镜像地址

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# create a directory with the registry name
sudo mkdir -p /var/snap/microk8s/current/args/certs.d/k8s.gcr.io

# create the hosts.toml file pointing to the mirror
echo '
server = "https://k8s.gcr.io"

[host."https://registry.aliyuncs.com/v2/google_containers"]
  capabilities = ["pull", "resolve"]
  override_path = true
' | sudo tee -a /var/snap/microk8s/current/args/certs.d/k8s.gcr.io/hosts.toml


# 2
sudo mkdir -p /var/snap/microk8s/current/args/certs.d/registry.k8s.io
echo '
server = "registry.k8s.io"

[host."https://registry.aliyuncs.com/v2/google_containers"]
  capabilities = ["pull", "resolve"]
  override_path = true
' | sudo tee -a /var/snap/microk8s/current/args/certs.d/registry.k8s.io/hosts.toml

需要重启

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sudo snap restart microk8s

检查状态

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# 如果不翻墙/替换镜像, 会在这里卡住
microk8s status --wait-ready

配置

配置 kubectl 命令

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mkdir -p ~/.local/bin/
vim ~/.local/bin/kubectl
# 输入如下内容
#!/bin/bash
exec /snap/bin/microk8s.kubectl $(echo "$*" | sed 's/-- sh.*/sh/')

配置别名

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# vim ~/.bash_aliases
alias kubectl='microk8s kubectl'
alias k='microk8s kubectl'
alias mk='microk8s'
alias helm='microk8s helm3'

设置私有镜像仓库

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$ docker login ... # 登录私有镜像仓库
$ kubectl create secret generic regcred \
    --from-file=.dockerconfigjson=$HOME/.docker/config.json \
    --type=kubernetes.io/dockerconfigjson \
    --namespace=default

组建集群

安装 dashboard

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microk8s enable dns dashboard
# 生成 token
microk8s kubectl create token -n kube-system default --duration=8544h

k8s.gcr.io 无法拉取镜像

配置 k8s.gcr.io 理论上可以解决问题。

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# pause
## 从阿里云镜像拉取
docker pull registry.aliyuncs.com/google_containers/pause:3.7
## 重命名
docker tag registry.aliyuncs.com/google_containers/pause:3.7 k8s.gcr.io/pause:3.7
docker tag registry.aliyuncs.com/google_containers/pause:3.7 registry.k8s.io/pause:3.7

# metric server
docker pull registry.aliyuncs.com/google_containers/metrics-server:v0.5.2
docker tag registry.aliyuncs.com/google_containers/metrics-server:v0.5.2 k8s.gcr.io/metrics-server/metrics-server:v0.5.2
docker tag registry.aliyuncs.com/google_containers/metrics-server:v0.5.2 registry.k8s.io/metrics-server/metrics-server:v0.5.2

Join 集群

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# master 节点运行
$ microk8s add-node
From the node you wish to join to this cluster, run the following:
microk8s join 192.168.1.230:25000/92b2db237428470dc4fcfc4ebbd9dc81/2c0cb3284b05

Use the '--worker' flag to join a node as a worker not running the control plane, eg:
microk8s join 192.168.1.230:25000/92b2db237428470dc4fcfc4ebbd9dc81/2c0cb3284b05 --worker

If the node you are adding is not reachable through the default interface you can use one of the following:
microk8s join 192.168.1.230:25000/92b2db237428470dc4fcfc4ebbd9dc81/2c0cb3284b05
microk8s join 10.23.209.1:25000/92b2db237428470dc4fcfc4ebbd9dc81/2c0cb3284b05
microk8s join 172.17.0.1:25000/92b2db237428470dc4fcfc4ebbd9dc81/2c0cb3284b05

# slave 节点运行
$ microk8s join 172.17.0.1:25000/92b2db237428470dc4fcfc4ebbd9dc81/2c0cb3284b05
架构►container►k8s

k8s 配置

k8s objects

官方文档。k8s objects 是 k8s 系统中的持久化实体，用来表示服务集群的状态。

Spec 和 Status

每个 k8s object 包含两个字段，spec 和 status。spec 是事先设置的期望的状态，由使用者指定。status 用来描述当前的状态，由 k8s 系统维护。

描述 k8s objects

当在 k8s 系统中创建 object 时，需要指定 object spec，来描述期望的状态，以及基础信息。

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apiVersion: apps/v1
kind: Deployment
metadata:
  # 部署的名字
  name: nginx-deployment
spec:
	# 用于选择要管理的Pod对象，该选择器匹配与Deployment相关联的Pod, 所有标签都匹配才行
  selector:
    matchLabels:
      app: nginx
  replicas: 2 # tells deployment to run 2 pods matching the template
  # 定义 pod 相关信息
  template:
    metadata:
      labels:
        app: nginx
    spec:
    	# 定义容器，可以多个
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80
        env:
          - name: ENV_NAME
        		value: ENV_VALUE
      # 按标签选择机器
      nodeSelector:
      	<label-name>: <label-value>
      # 设置机器亲和性
      affinity:
        # 设置 node 亲和性
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
              - matchExpressions:
                  - key: <label-name>
                    operator: In
                    values:
                      - <label-value>
        # 设置 pod 亲和性
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions:
                  - key: app.kubernetes.io/name
                    operator: In
                    values:
                      - <pod-name>
                      - <pod-name>
              topologyKey: kubernetes.io/hostname

需要的字段

  • apiVersion - 创建 k8s object 时使用的 API 版本
  • kind - 创建的 object 的类型
  • metadata - 用来唯一标识 object，包括 name、UID、namespace
  • spec - k8s object 期望的状态

服务

端口

  • ClusterIP，集群内可以访问，也可以使用 port-forward （用于测试）的方式访问
  • NodePort，直接通过节点访问（k8s 节点，master & work）
    • 需要定义 nodePort
    • 不同的流量会被转发到不同的 pod
  • LoadBalancer，负载均衡方式访问（需要负载均衡器）