106、Label 控制 Service的位置 （Swarm13）

参考https://www.cnblogs.com/CloudMan6/p/8038799.html

 

上一节我们讨论了 Service部署的两种模式，global mode 和 replicated mode 。无论global mode 还是replicated mode ，副本运行在哪些节点都是由Swarm决定的。

 

那么作为用户我们没有可能精细控制 Service运行的位置呢？ 答案是：能 ， 使用label

 

过程分两步：

    1、为每个node 定义label

    2、设置Service运行在指定label的node上

 

label 可以灵活的描述node的属性，其形式是 key = value ，用户可以任意指定，例如将 swarm-worker1 作为测试环境，为其添加label env=test

 

host01标记为测试环境，host02标记为线上环境

 

root@host03:~# docker node update --label-add env=test host01    #    将host01标记为测试环境

host01

 

root@host03:~# docker node inspect host01 --pretty

ID:            hvt2ez9e7zvqm2hz8nix1eke7

Labels:

- env=test

Hostname:                  host01

Joined at:                 2019-05-14 03:19:30.200301075 +0000 utc

Status:

State:            Ready

Availability:             Active

Address:        10.12.31.211

 

root@host03:~# docker node update --label-add env=prod host02    #    将host02标记为线上环境

host02

root@host03:~# docker node inspect host02 --pretty

ID:            asn5ufnogzkyqigk4mizatoer

Labels:

- env=prod

Hostname:                  host02

Joined at:                 2019-05-14 03:19:34.507855133 +0000 utc

Status:

State:            Ready

Availability:             Active

Address:        10.12.31.212

 

在测试环境创建Service my_web ，副本数 3

 

root@host03:~# docker service create --name my_web --replicas 3 --constraint node.labels.env==test --publish 80:80 httpd

addp6i8pm0msmamq6a4oc94py

overall progress: 3 out of 3 tasks

1/3: running   [==================================================>]

2/3: running   [==================================================>]

3/3: running   [==================================================>]

verify: Service converged

root@host03:~# docker service ps my_web    #    确认所有的副本都在测试环境的node上

ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE            ERROR               PORTS

63mta4uzj5kh        my_web.1            httpd:latest        host01              Running             Running 11 seconds ago                       

svynuplsq5l9        my_web.2            httpd:latest        host01              Running             Running 11 seconds ago                       

y8ion2zxr2fb        my_web.3            httpd:latest        host01              Running             Running 11 seconds ago                       

root@host03:~# docker service inspect my_web --pretty

ID:        addp6i8pm0msmamq6a4oc94py

Name:        my_web

Service Mode:    Replicated

Replicas:    3

Placement:

Constraints:    [node.labels.env==test]

 

 

将 my_web 的Service 从测试环境迁移到线上环境

 

root@host03:~# docker service update --constraint-rm node.labels.env==test my_web    #    删除Service 测试环境的标签

my_web

overall progress: 3 out of 3 tasks

1/3: running   [==================================================>]

2/3: running   [==================================================>]

3/3: running   [==================================================>]

verify: Service converged

root@host03:~# docker service ps my_web

ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE           ERROR               PORTS

63mta4uzj5kh        my_web.1            httpd:latest        host01              Running             Running 4 minutes ago                       

svynuplsq5l9        my_web.2            httpd:latest        host01              Running             Running 4 minutes ago                       

y8ion2zxr2fb        my_web.3            httpd:latest        host01              Running             Running 4 minutes ago                       

root@host03:~# docker service update --constraint-add node.labels.env==prod my_web    #    添加Service 线上环境的标签

my_web

overall progress: 3 out of 3 tasks

1/3: running   [==================================================>]

2/3: running   [==================================================>]

3/3: running   [==================================================>]

verify: Service converged

root@host03:~# docker service ps my_web

ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE             ERROR               PORTS

mj39f4gddt7g        my_web.1            httpd:latest        host02              Running             Running 17 seconds ago                        

63mta4uzj5kh         \_ my_web.1        httpd:latest        host01              Shutdown            Shutdown 18 seconds ago                       

r82s4x7t8cft        my_web.2            httpd:latest        host02              Running             Running 12 seconds ago                        

svynuplsq5l9         \_ my_web.2        httpd:latest        host01              Shutdown            Shutdown 13 seconds ago                       

nxu3gvglcn5y        my_web.3            httpd:latest        host02              Running             Running 8 seconds ago                         

y8ion2zxr2fb         \_ my_web.3        httpd:latest        host01              Shutdown            Shutdown 9 seconds ago                

 

label 与 global mode 组合，只收集线上环境的日志

 

root@host03:~# docker service create --mode global --constraint node.labels.env==prod --name monitor busybox sleep 99999

vbo0n6hgrr8qehw1kql3znk4y

overall progress: 1 out of 1 tasks

asn5ufnogzky: running   [==================================================>]

verify: Service converged

root@host03:~# docker service ps monitor

ID                  NAME                                IMAGE               NODE                DESIRED STATE       CURRENT STATE            ERROR               PORTS

bek7a8mt387i        monitor.asn5ufnogzkyqigk4mizatoer   busybox:latest      host02              Running             Running 24 seconds ago