docker 1.12 版本 docker swarm 集羣

時間 2019-11-22

標籤 docker 1.12 版本 swarm 集羣欄目 Docker 简体版

原文原文鏈接

docker 1.12 版本的新特性html

（1）docker swarm：集羣管理，子命令有init, join, leave, updatenode

（2）docker service：服務建立，子命令有create, inspect, update, remove, taskslinux

（3）docker node：節點管理，子命令有accept, promote, demote, inspect, update, tasks, ls, rmnginx

（4）docker stack/deploy：試驗特性，用於多應用部署，相似與 docker-compose 中的特性。git

我在使用的時候仍是測試版本，因此使用 github

wget -qO- https://test.docker.com/ | sh

進行安裝配置web

安裝完畢之後:docker

[root@swarm-manager ~]# docker version
Client:
 Version:      1.12.0-rc2
 API version:  1.24
 Go version:   go1.6.2
 Git commit:   906eacd
 Built:        
 OS/Arch:      linux/amd64

Server:
 Version:      1.12.0-rc2
 API version:  1.24
 Go version:   go1.6.2
 Git commit:   906eacd
 Built:        
 OS/Arch:      linux/amd64

1、咱們首先來看看 1.12 中新特性裏面的內置 swarm 命令（swarmkit採用raft協議構建集羣）網絡

[root@swarm-manager ~]# docker swarm --help

Usage: docker swarm COMMAND

Manage Docker Swarm

Options:
--help Print usage

Commands:
init Initialize a Swarm
join Join a Swarm as a node and/or manager
update Update the Swarm
leave Leave a Swarm
inspect Inspect the Swarm

Run 'docker swarm COMMAND --help' for more information on a command.

這裏命令有 5個tcp

Commands:

init Initialize a Swarm

join Join a Swarm as a node and/or manager

update Update the Swarm

leave Leave a Swarm

inspect Inspect the Swarm

1. init 初始化，一個 Swarm 集羣，執行效果：

[root@swarm-manager ~]# docker swarm init
Swarm initialized: current node (0vwpni05mew2j84i6gjet44iu) is now a manager.

這裏顯示初始化了一個 Swarm 集羣，並把這機器作爲管理節點。

[root@swarm-manager ~]#docker node ls
ID                           NAME                   MEMBERSHIP  STATUS  AVAILABILITY  MANAGER STATUS
0vwpni05mew2j84i6gjet44iu *  swarm-manager          Accepted    Ready   Active        Leader

執行 docker node ls 能夠查看 Swarm 的集羣狀況（只能在 manager 中執行）

[root@swarm-manager ~]# netstat -lan|grep 2377

能夠看到羣集開放了一這個 2377 的端口。

默認綁定 0.0.0.0:2377 ，固然咱們也可使用 docker swarm init --listen-addr <MANAGER-IP>:<PORT> 進行綁定ip

2377 這個端口是用於 Swarm 中 node 節點加入使使用的。

2. join 加入 Swarm 集羣, 可加入作爲 node 節點，也可加入做爲管理節點。

[root@swarm-node-1 ~]#docker swarm join 10.6.0.140:2377
This node joined a Swarm as a worker.

這裏在 node-1 裏面執行了 join 命令，加入了 10.6.0.140 這個 manager 這個 Swarm 集羣裏

[root@swarm-manager ~]#docker node ls           
ID                           NAME                   MEMBERSHIP  STATUS  AVAILABILITY  MANAGER STATUS
0vwpni05mew2j84i6gjet44iu *  swarm-manager          Accepted    Ready   Active        Leader
4mqsmp0gzlqeicit98ce8wh2q    swarm-node-1           Accepted    Ready   Active

這裏能夠看到 node-1 已經加入到 swarm 的集羣裏面來了。

3. update 命令, 只提示 updated ，具體做用尚不明白，應該是馬上刷新 swarm 的羣集信息

[root@swarm-manager ~]#docker swarm update
Swarm updated.

4. leave 命令，離開 Swarm 集羣，一個docker 只能加入一個node.

[root@swarm-node-1 ~]#docker swarm leave 10.6.0.140:2377

5. inspect 命令，查詢 Swarm 集羣的總體信息。（只能在 manager 中執行）

[root@swarm-manager ~]#docker swarm inspect
[
    {
        "ID": "c052zw5ll0ugw08shg2xf7ajp",
        "Version": {
            "Index": 11
        },
        "CreatedAt": "2016-06-23T02:09:18.935434519Z",
        "UpdatedAt": "2016-06-23T02:09:19.155114277Z",
        "Spec": {
            "Name": "default",
            "AcceptancePolicy": {
                "Policies": [
                    {
                        "Role": "worker",
                        "Autoaccept": true
                    },
                    {
                        "Role": "manager",
                        "Autoaccept": false
                    }
                ]
            },
            "Orchestration": {
                "TaskHistoryRetentionLimit": 10
            },
            "Raft": {
                "SnapshotInterval": 10000,
                "LogEntriesForSlowFollowers": 500,
                "HeartbeatTick": 1,
                "ElectionTick": 3
            },
            "Dispatcher": {
                "HeartbeatPeriod": 5000000000
            },
            "CAConfig": {
                "NodeCertExpiry": 7776000000000000
            }
        }
    }
]

2、接下來咱們來看看 service 命令。

[root@swarm-manager ~]#docker service --help

Usage:  docker service COMMAND

Manage Docker services

Options:
      --help   Print usage

Commands:
  create      Create a new service
  inspect     Inspect a service
  tasks       List the tasks of a service
  ls          List services
  rm          Remove a service
  scale       Scale one or multiple services
  update      Update a service

Run 'docker service COMMAND --help' for more information on a command.

1. docker create 命令，既建立一個服務。

[root@swarm-manager ~]#docker service create --help

Usage:  docker service create [OPTIONS] IMAGE [COMMAND] [ARG...]

Create a new service

Options:
      --constraint value             Placement constraints (default [])
      --endpoint-mode string         Endpoint mode(Valid values: VIP, DNSRR)
  -e, --env value                    Set environment variables (default [])
      --help                         Print usage
  -l, --label value                  Service labels (default [])
      --limit-cpu value              Limit CPUs (default 0.000)
      --limit-memory value           Limit Memory (default 0 B)
      --mode string                  Service mode (replicated or global) (default "replicated")
  -m, --mount value                  Attach a mount to the service
      --name string                  Service name
      --network value                Network attachments (default [])
  -p, --publish value                Publish a port as a node port (default [])
      --replicas value               Number of tasks (default none)
      --reserve-cpu value            Reserve CPUs (default 0.000)
      --reserve-memory value         Reserve Memory (default 0 B)
      --restart-condition string     Restart when condition is met (none, on_failure, or any)
      --restart-delay value          Delay between restart attempts (default none)
      --restart-max-attempts value   Maximum number of restarts before giving up (default none)
      --restart-window value         Window used to evalulate the restart policy (default none)
      --stop-grace-period value      Time to wait before force killing a container (default none)
      --update-delay duration        Delay between updates
      --update-parallelism uint      Maximum number of tasks updated simultaneously
  -u, --user string                  Username or UID
  -w, --workdir string               Working directory inside the container

docker service create 裏面有很是多的參數。這裏有很詳細的使用說明。

下面咱們來建立一個 service 試試看

首先pull 一個 nginx 鏡像下來用於測試

[root@swarm-manager ~]#docker pull nginx

建立 2 個 nginx :

[root@swarm-manager ~]#docker service create --name nginx --replicas 2 -p 80:80/tcp nginx

使用 docker service ls 可查看服務啓動狀況。

[root@swarm-manager ~]#docker service ls
ID            NAME   REPLICAS  IMAGE  COMMAND
1b9a58mlz330  nginx  1/2       nginx

使用 tasks 命令可查看 nginx 的狀況。

[root@swarm-manager ~]#docker service tasks nginx
ID                         NAME     SERVICE  IMAGE  LAST STATE           DESIRED STATE  NODE
56er48j3hin9ysdi3sb1chbn1  nginx.1  nginx    nginx  Preparing 2 minutes  Running        swarm-node-1
e7vtvpkbstznoi8ogihaao1f5  nginx.2  nginx    nginx  Running 2 minutes    Running        swarm-manager

這裏顯示 swarm-node-1 節點中 last state 的狀態爲 preparing .

緣由是 swarm-node-1 節點並無 nginx 的鏡像

在 node-1 節點pull nginx 鏡像。

[root@swarm-node-1 ~]#docker pull nginx

node-1 節點pull 完畢之後，在使用 service ls 查看，服務已經自動啓動了。

Swarm模式下的引擎擁有自組織與自修復特性，意味着它們可以識別咱們定義的應用，並在出現差錯時持續檢查並修復環境。

舉例來講，若是你們關閉某臺運行有Nginx實例的設備，則另外一節點上會自動啓動一套新的容器。

若是關閉Swarm內半數設備所使用的網絡交換機，則另一半設備會頂替而上，接管對應工做負載。

[root@swarm-manager ~]#docker service ls
ID            NAME   REPLICAS  IMAGE  COMMAND
1b9a58mlz330  nginx  2/2       nginx

[root@swarm-manager ~]#docker service tasks nginx
ID                         NAME     SERVICE  IMAGE  LAST STATE          DESIRED STATE  NODE
56er48j3hin9ysdi3sb1chbn1  nginx.1  nginx    nginx  Running 32 minutes  Running        swarm-node-1
e7vtvpkbstznoi8ogihaao1f5  nginx.2  nginx    nginx  Running 32 minutes  Running        swarm-manager

2. docker service scale 命令，這個命令是批量生成已有容器。

直接對 nginx=10 既可以讓 nginx 的容器生成10個。

[root@swarm-manager ~]#docker service scale nginx=10
nginx scaled to 10

使用 tasks 能夠看到，已經在 2個節點中生成了10個 nginx 容器

[root@swarm-manager ~]#docker service tasks nginx
ID                         NAME      SERVICE  IMAGE  LAST STATE            DESIRED STATE  NODE
56er48j3hin9ysdi3sb1chbn1  nginx.1   nginx    nginx  Running 43 minutes    Running        swarm-node-1
e7vtvpkbstznoi8ogihaao1f5  nginx.2   nginx    nginx  Running 43 minutes    Running        swarm-manager
9vqxcmskj1nawo8wl0fqr32j2  nginx.3   nginx    nginx  Preparing 20 seconds  Running        swarm-manager
0vbqoyestm7ob6r1zq9jwj6il  nginx.4   nginx    nginx  Running 20 seconds    Running        swarm-node-1
13jf9mkl4k5e57pq4hoeb68ru  nginx.5   nginx    nginx  Running 20 seconds    Running        swarm-node-1
a0tk6ni6a02diuo5u3t870qk7  nginx.6   nginx    nginx  Running 20 seconds    Running        swarm-manager
cwplvo5wfqp3rn5ynvxv9wv90  nginx.7   nginx    nginx  Running 20 seconds    Running        swarm-manager
7feil5xqc5hdkseasthkq2nyx  nginx.8   nginx    nginx  Running 20 seconds    Running        swarm-node-1
8jt5yovxoz7t89edinb9ydao1  nginx.9   nginx    nginx  Starting 20 seconds   Running        swarm-node-1
dst4ydun1upham0o7e8a9hj3w  nginx.10  nginx    nginx  Running 20 seconds    Running        swarm-manager

當咱們想縮容時間，也可使用 scale nginx=2 讓容器變成2個。

[root@swarm-manager ~]#docker service scale nginx=2
nginx scaled to 2

在運行 nginx=2 時能夠看到容器已經縮小爲 2個。

當咱們使用 docker ps 查看，會發現容器被 stop 而非 rm 。

當咱們使用 docker service rm nginx 的時候，全部的容器都會被刪除，請注意。

[root@swarm-manager ~]#docker service tasks nginx
ID                         NAME     SERVICE  IMAGE  LAST STATE          DESIRED STATE  NODE
0vbqoyestm7ob6r1zq9jwj6il  nginx.4  nginx    nginx  Running 12 minutes  Running        swarm-node-1
13jf9mkl4k5e57pq4hoeb68ru  nginx.5  nginx    nginx  Running 12 minutes  Running        swarm-node-1

3. docker service update 命令。可對服務的啓動參數進行更新/修改。

上面咱們新建了一個服務，命令爲：

[root@swarm-manager ~]#docker service create --name nginx --replicas 2 -p 80:80/tcp nginx

若是咱們先新加入了一個 node 想讓 nginx 分佈在 3個 node 上面，咱們可使用 update 命令。

[root@swarm-manager ~]#docker service update --replicas 3 nginx
nginx

更新完畢之後咱們能夠查看到 REPLICAS 已經變成 3/3

[root@swarm-manager ~]#docker service ls
ID            NAME   REPLICAS  IMAGE  COMMAND
1b9a58mlz330  nginx  3/3       nginx

docker service update 命令，也可用於直接升級鏡像等。

[root@swarm-manager ~]#docker service tasks nginx
ID                         NAME     SERVICE  IMAGE  LAST STATE           DESIRED STATE  NODE
0vbqoyestm7ob6r1zq9jwj6il  nginx.4  nginx    nginx  Running 41 minutes   Running        swarm-node-1
340e1u31vadq3jtebzeddmatt  nginx.5  nginx    nginx  Preparing 5 seconds  Running        swarm-manager

上面咱們使用了 nginx 鏡像啓動了任務。使用 update --image 可直接對 image 進行更新。

[root@swarm-manager ~]#docker service update --image nginx:new nginx 
nginx

能夠看到 IMAGE 已經變成 nginx:new

[root@swarm-manager ~]#docker service tasks nginx
ID                         NAME     SERVICE  IMAGE      LAST STATE          DESIRED STATE  NODE
2ba3utpk6icf0w449kcwgxmnm  nginx.4  nginx    nginx:new  Running 49 seconds  Running        swarm-manager
5wmmneiueeool09fs8d2g1ncq  nginx.5  nginx    nginx:new  Running 49 seconds  Running        swarm-node-1

掛載目錄, mount


docker service create --mount type=bind,target=/container_data/,source=/host_data/

例 - 本地目錄：     target = 容器裏面的路徑， source = 本地硬盤路徑
docker service create --name nginx --mount type=bind,target=/usr/share/nginx/html/,source=/opt/web/ --replicas 2 --publish 80:80/tcp nginx



docker service create --mount type=volume,source=<VOLUME-NAME>,target=<CONTAINER-PATH>,volume-driver=<DRIVER>,

例 - 掛載volume卷：  source  =  volume 名稱 ,  traget = 容器裏面的路徑
docker service create --name nginx --mount type=volume,source=myvolume,target=/usr/share/nginx/html,volume-driver=local --replicas 2 --publish 80:80/tcp nginx

3、下面是 node , node命令用於節點管理:

[root@swarm-manager ~]#docker node --help

Usage:  docker node COMMAND

Manage Docker Swarm nodes

Options:
      --help   Print usage

Commands:
  accept      Accept a node in the swarm
  demote      Demote a node from manager in the swarm
  inspect     Inspect a node in the swarm
  ls          List nodes in the swarm
  promote     Promote a node to a manager in the swarm
  rm          Remove a node from the swarm
  tasks       List tasks running on a node
  update      Update a node

Run 'docker node COMMAND --help' for more information on a command.