mirror of https://github.com/easzlab/kubeasz.git
156 lines
5.2 KiB
Markdown
156 lines
5.2 KiB
Markdown
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## 04-安装docker服务.md
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``` bash
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roles/docker/
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├── files
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│ ├── daemon.json
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│ ├── docker
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│ └── docker-tag
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├── tasks
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│ └── main.yml
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└── templates
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└── docker.service.j2
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```
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请在另外窗口打开[roles/docker/tasks/main.yml](../roles/docker/tasks/main.yml) 文件,对照看以下讲解内容。
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### 创建docker的systemd unit文件
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``` bash
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[Unit]
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Description=Docker Application Container Engine
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Documentation=http://docs.docker.io
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[Service]
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Environment="PATH={{ bin_dir }}:/bin:/sbin:/usr/bin:/usr/sbin"
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ExecStart={{ bin_dir }}/dockerd
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ExecStartPost=/sbin/iptables -I FORWARD -s 0.0.0.0/0 -j ACCEPT
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ExecReload=/bin/kill -s HUP $MAINPID
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Restart=on-failure
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RestartSec=5
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LimitNOFILE=infinity
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LimitNPROC=infinity
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LimitCORE=infinity
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Delegate=yes
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KillMode=process
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[Install]
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WantedBy=multi-user.target
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```
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+ dockerd 运行时会调用其它 docker 命令,如 docker-proxy,所以需要将 docker 命令所在的目录加到 PATH 环境变量中;
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+ docker 从 1.13 版本开始,将`iptables` 的`filter` 表的`FORWARD` 链的默认策略设置为`DROP`,从而导致 ping 其它 Node 上的 Pod IP 失败,因此必须在 `filter` 表的`FORWARD` 链增加一条默认允许规则 `iptables -I FORWARD -s 0.0.0.0/0 -j ACCEPT`
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+ 运行`dockerd --help` 查看所有可配置参数,确保默认开启 `--iptables` 和 `--ip-masq` 选项
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### 配置国内镜像加速
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从国内下载docker官方仓库镜像非常缓慢,所以对于k8s集群来说配置镜像加速非常重要,配置 `/etc/docker/daemon.json`
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``` bash
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{
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"registry-mirrors": ["https://registry.docker-cn.com"],
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"max-concurrent-downloads": 10,
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"log-driver": "json-file",
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"log-level": "warn",
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"log-opts": {
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"max-size": "10m",
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"max-file": "3"
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}
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}
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```
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这将在后续部署calico下载 calico/node镜像和kubedns/heapster/dashboard镜像时起到重要加速效果。
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由于K8S的官方镜像存放在`gcr.io`仓库,因此这个镜像加速对K8S的官方镜像没有效果;好在`Docker Hub`上有很多K8S镜像的转存,而`Docker Hub`上的镜像可以加速。这里推荐两个K8S镜像的`Docker Hub`项目,几乎能找到所有K8S相关的镜像,而且更新及时,感谢维护者的辛勤付出!
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+ [mirrorgooglecontainers](https://hub.docker.com/u/mirrorgooglecontainers/)
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+ [anjia0532](https://hub.docker.com/u/anjia0532/), [项目github地址](https://github.com/anjia0532/gcr.io_mirror)
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当然对于企业内部应用的docker镜像,想要在K8S平台运行的话,特别是结合开发`CI/CD` 流程,肯定是需要部署私有镜像仓库的,后续会简单提到 `Harbor`的部署。
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另外,daemon.json配置中也配置了docker 容器日志相关参数,设置单个容器日志超过10M则进行回卷,回卷的副本数超过3个就进行清理。
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### 清理 iptables
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因为后续`calico`网络、`kube-proxy`等将大量使用 iptables规则,安装前清空所有`iptables`策略规则;常见发行版`Ubuntu`的 `ufw` 和 `CentOS`的 `firewalld`等基于`iptables`的防火墙最好直接卸载,避免不必要的冲突。
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``` bash
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iptables -F && iptables -X \
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&& iptables -F -t nat && iptables -X -t nat \
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&& iptables -F -t raw && iptables -X -t raw \
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&& iptables -F -t mangle && iptables -X -t mangle
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```
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+ calico 网络支持 `network-policy`,使用的`calico-kube-controllers` 会使用到`iptables` 所有的四个表 `filter` `nat` `raw` `mangle`,所以一并清理
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### 启动 docker 略
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### 可选-安装docker查询镜像 tag的小工具
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docker官方目前没有提供在命令行直接查询某个镜像的tag信息的方式,网上找来一个脚本工具,使用很方便。
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``` bash
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$ docker-tag library/ubuntu
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"14.04"
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"16.04"
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"17.04"
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"latest"
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"trusty"
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"trusty-20171117"
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"xenial"
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"xenial-20171114"
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"zesty"
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"zesty-20171114"
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$ docker-tag mirrorgooglecontainers/kubernetes-dashboard-amd64
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"v0.1.0"
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"v1.0.0"
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"v1.0.0-beta1"
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"v1.0.1"
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"v1.1.0-beta1"
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"v1.1.0-beta2"
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"v1.1.0-beta3"
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"v1.7.0"
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"v1.7.1"
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"v1.8.0"
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```
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+ 需要先apt安装轻量JSON处理程序 `jq`
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+ 然后下载脚本即可使用
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+ 脚本很简单,就一行命令如下
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``` bash
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#!/bin/bash
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curl -s -S "https://registry.hub.docker.com/v2/repositories/$@/tags/" | jq '."results"[]["name"]' |sort
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```
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+ 对于 CentOS7 安装 `jq` 稍微费力一点,需要启用 `EPEL` 源
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``` bash
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wget http://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
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rpm -ivh epel-release-latest-7.noarch.rpm
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yum install jq
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```
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### 验证
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运行`ansible-playbook 03.docker.yml` 成功后可以验证
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``` bash
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systemctl status docker # 服务状态
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journalctl -u docker # 运行日志
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docker version
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docker info
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```
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`iptables-save|grep FORWARD` 查看 iptables filter表 FORWARD链,最后要有一个 `-A FORWARD -j ACCEPT` 保底允许规则
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``` bash
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iptables-save|grep FORWARD
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:FORWARD ACCEPT [0:0]
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:FORWARD DROP [0:0]
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-A FORWARD -j DOCKER-USER
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-A FORWARD -j DOCKER-ISOLATION
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-A FORWARD -o docker0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
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-A FORWARD -o docker0 -j DOCKER
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-A FORWARD -i docker0 ! -o docker0 -j ACCEPT
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-A FORWARD -i docker0 -o docker0 -j ACCEPT
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-A FORWARD -j ACCEPT
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```
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[前一篇](02-安装etcd集群.md) -- [后一篇](05-安装kube-master节点.md)
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