deploy service on swarm

转自：https://www.cnblogs.com/jsonhc/p/7852530.html

swarm集群配置完成后，查看一些基本的信息：

[root@manager1 ~]# docker-machine ls
NAME       ACTIVE   DRIVER    STATE     URL                         SWARM   DOCKER        ERRORS
manager1   -        generic   Running   tcp://192.168.101.14:2376           v17.09.0-ce   
work1      -        generic   Running   tcp://192.168.101.15:2376           v17.10.0-ce 

查看节点信息：

[root@manager1 ~]# docker node ls
ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS
4ecjeeu8273dzsmfta7u6op9t *   manager1            Ready               Active              Leader
sn7c5u5wtupgt3qpz22o117hl     work1               Ready               Active  

如果需要更新详细的查看节点信息：

[root@manager1 ~]# docker node inspect --pretty manager1
ID:                     4ecjeeu8273dzsmfta7u6op9t
Hostname:               manager1
Joined at:              2017-11-15 18:28:21.103210247 +0000 utc
Status:
 State:                 Ready
 Availability:          Active
 Address:               192.168.101.14
Manager Status:
 Address:               192.168.101.14:2377
 Raft Status:           Reachable
 Leader:                Yes
Platform:
 Operating System:      linux
 Architecture:          x86_64
Resources:
 CPUs:                  2
 Memory:                3.686GiB
Plugins:
 Log:           awslogs, fluentd, gcplogs, gelf, journald, json-file, logentries, splunk, syslog
 Network:               bridge, host, macvlan, null, overlay
 Volume:                local
Engine Version:         17.09.0-ce
Engine Labels:
 - provider=generic
TLS Info:
 TrustRoot:
-----BEGIN CERTIFICATE-----
MIIBazCCARCgAwIBAgIUPDGTCzw2cZelyvysFW+jcF3PcQMwCgYIKoZIzj0EAwIw
EzERMA8GA1UEAxMIc3dhcm0tY2EwHhcNMTcxMTE1MTgyMzAwWhcNMzcxMTEwMTgy
MzAwWjATMREwDwYDVQQDEwhzd2FybS1jYTBZMBMGByqGSM49AgEGCCqGSM49AwEH
A0IABNyMg4cqG1XaXB6g5PbNGxjishle1cPF9t0kn5LbRKwh+IGwDZD2fdbli2bk
9fzVQVWCj3aZzCyyVSFxZ30+cPWjQjBAMA4GA1UdDwEB/wQEAwIBBjAPBgNVHRMB
Af8EBTADAQH/MB0GA1UdDgQWBBTElfvEWZqpfIfCYCr+Vn6peYGOPDAKBggqhkjO
PQQDAgNJADBGAiEAh44+/Ns5T+MwiD49jXmIpr7mz/8qyMEvFDtk55j5eQ0CIQCP
HEbLBRkJWxqNs6p5O+emfvIVpFHuy/X8K6tDF7qmiw==
-----END CERTIFICATE-----

 Issuer Subject:        MBMxETAPBgNVBAMTCHN3YXJtLWNh
 Issuer Public Key:     MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE3IyDhyobVdpcHqDk9s0bGOKyGV7Vw8X23SSfkttErCH4gbANkPZ91uWLZuT1/NVBVYKPdpnMLLJVIXFnfT5w9Q==

现在利用docker service命令来创建服务：

[root@manager1 ~]# docker service create --name web --replicas 2 nginx
oq2jsjc4zhwtpcwqqd2whj701
Since --detach=false was not specified, tasks will be created in the background.
In a future release, --detach=false will become the default.

其中的参数：--name表示创建服务的名称，--replicas表示创建的副本数，nginx是镜像

查看创建好的service：

[root@manager1 ~]# docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE               PORTS
oq2jsjc4zhwt        web                 replicated          2/2                 nginx:latest   

查看service服务在节点的运行情况：

[root@manager1 ~]# docker service ps web
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE           ERROR               PORTS
rk7pyq7pr49b        web.1               nginx:latest        work1               Running             Running 7 seconds ago                       
w3orhk7uzvzy        web.2               nginx:latest        manager1            Running             Running 7 seconds ago 

如果在创建的过程中出现如下报错：

[root@manager1 ~]# docker service ps web
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE             ERROR                              PORTS
klcan0r46jih        web.1               nginx:latest        work1               Ready               Preparing 3 seconds ago                                      
ypx26zy1gp63         \_ web.1           nginx:latest        work1               Shutdown            Rejected 3 seconds ago    "No such image: nginx:latest@s…"   
dy51asan25pf        web.2               nginx:latest        manager1            Running             Running 18 seconds ago

work1节点上没有相应的镜像，导致启动失败，可能的原因之一：work1节点使用的默认的官方镜像源，所以下载缓慢，导致失败，解决办法：将work1节点配置镜像加速器重启docker服务就行

如果需要详细查看service信息：

[root@manager1 ~]# docker service inspect --pretty web

ID:             oq2jsjc4zhwtpcwqqd2whj701
Name:           web
Service Mode:   Replicated
 Replicas:      2
Placement:
UpdateConfig:
 Parallelism:   1
 On failure:    pause
 Monitoring Period: 5s
 Max failure ratio: 0
 Update order:      stop-first
RollbackConfig:
 Parallelism:   1
 On failure:    pause
 Monitoring Period: 5s
 Max failure ratio: 0
 Rollback order:    stop-first
ContainerSpec:
 Image:         nginx:latest@sha256:9fca103a62af6db7f188ac3376c60927db41f88b8d2354bf02d2290a672dc425
Resources:
Endpoint Mode:  vip

如果需要访问容器提供的服务，需要为容器进行映射端口：

[root@manager1 ~]# docker service update --publish-add 8080:80 web
web

使用命令update进行对服务的修改，更新等等操作

[root@manager1 ~]# docker service ps web
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE                    ERROR               PORTS
jzq72hlu434g        web.1               nginx:latest        work1               Running             Running less than a second ago                       
rk7pyq7pr49b         \_ web.1           nginx:latest        work1               Shutdown            Shutdown 1 second ago                                
ys5voif2df7f        web.2               nginx:latest        manager1            Running             Running 2 seconds ago                                
w3orhk7uzvzy         \_ web.2           nginx:latest        manager1            Shutdown            Shutdown 3 seconds ago 

[root@manager1 ~]# docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE               PORTS
oq2jsjc4zhwt        web                 replicated          2/2                 nginx:latest        *:8080->80/tcp

然后进行访问web服务：

这里创建的服务在节点manager1和worl1上（192.168.101.14、192.168.101.15），不指定为什么创建的service一直没有实现负载均衡，一直只是manager1节点能够提供访问，这个问题等待解决

上面可以看出service由manager1、work1两个节点提供，现在将其中的某一个节点进行下线：

[root@manager1 ~]# docker node update --availability drain work1
work1
[root@manager1 ~]# docker node ls
ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS
4ecjeeu8273dzsmfta7u6op9t *   manager1            Ready               Active              Leader
sn7c5u5wtupgt3qpz22o117hl     work1               Ready               Drain   

节点的availability的值可以显示节点的状态（active表示活跃在线，drain表示下线不提供服务或者处于维护状态）

将节点wrok1下线后，查看服务的replicas数量：

[root@manager1 ~]# docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE               PORTS
oq2jsjc4zhwt        web                 replicated          2/2                 nginx:latest        *:8080->80/tcp

可以看见service web的replicas并没有减少：

[root@manager1 ~]# docker service ps web
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE                 ERROR               PORTS
o0p9zt3su44g        web.1               nginx:latest        manager1            Running             Running about a minute ago                        
jzq72hlu434g         \_ web.1           nginx:latest        work1               Shutdown            Shutdown about a minute ago                       
rk7pyq7pr49b         \_ web.1           nginx:latest        work1               Shutdown            Shutdown 6 minutes ago                            
ys5voif2df7f        web.2               nginx:latest        manager1            Running             Running 6 minutes ago                             
w3orhk7uzvzy         \_ web.2           nginx:latest        manager1            Shutdown            Shutdown 6 minutes ago  

而提供服务的节点由之前的manager1和worlk1共同提供变成了只由节点manager1提供：

现在将work1节点进行更改为active：

[root@manager1 ~]# docker node update --availability active work1
work1
[root@manager1 ~]# docker node ls                                
ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS
4ecjeeu8273dzsmfta7u6op9t *   manager1            Ready               Active              Leader
sn7c5u5wtupgt3qpz22o117hl     work1               Ready               Active  

当work1节点上线后，但是work1并没有抢回提供服务：

[root@manager1 ~]# docker service ps web                         
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE            ERROR               PORTS
o0p9zt3su44g        web.1               nginx:latest        manager1            Running             Running 4 minutes ago                        
jzq72hlu434g         \_ web.1           nginx:latest        work1               Shutdown            Shutdown 4 minutes ago                       
rk7pyq7pr49b         \_ web.1           nginx:latest        work1               Shutdown            Shutdown 9 minutes ago                       
ys5voif2df7f        web.2               nginx:latest        manager1            Running             Running 9 minutes ago                        
w3orhk7uzvzy         \_ web.2           nginx:latest        manager1            Shutdown            Shutdown 9 minutes ago 

现在将service的replicas进行伸缩或者扩展，这里将replicas增加到3（现在数量为2）

[root@manager1 ~]# docker service scale web=3
web scaled to 3

[root@manager1 ~]# docker service ps web     
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE             ERROR               PORTS
o0p9zt3su44g        web.1               nginx:latest        manager1            Running             Running 6 minutes ago                         
jzq72hlu434g         \_ web.1           nginx:latest        work1               Shutdown            Shutdown 6 minutes ago                        
rk7pyq7pr49b         \_ web.1           nginx:latest        work1               Shutdown            Shutdown 11 minutes ago                       
ys5voif2df7f        web.2               nginx:latest        manager1            Running             Running 11 minutes ago                        
w3orhk7uzvzy         \_ web.2           nginx:latest        manager1            Shutdown            Shutdown 11 minutes ago                       
g0liotj1z9j6        web.3               nginx:latest        work1               Running             Running 1 second ago 

可以看见work1节点又开始为web提供服务了

删除掉上面创建的服务，重新创建新的服务，使用--publish：

[root@manager1 ~]# docker service rm web
web