warm as a worker.
- 在w1上做同样的操作;
- 在m0、m1、m2其中的任意一台上执行命令docker node ls查看Swarm集群的现状,可见工作节点已经全部就绪:
[root@m0 ~]# docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
0isfyre69mdu1hm11esf1q3dk m2 Ready Active Reachable
7585zt09o2sat82maef0ocf42 * m0 Ready Active Leader
i71bcxt1auc804syybroajtan w1 Ready Active
slc0hjbs7jh2hdi8ai3wohy23 m1 Ready Active Reachable
wqcwcccva3d3mxgi5p423d4fv w0 Ready Active
至此,Swarm集群环境搭建完毕,接下来可以验证了。
验证Swarm集群环境
- 创建名为tomcat-net的覆盖网络(Overlay Netowork),这是个二层网络,处于该网络下的docker容器,即使宿主机不一样,也能相互访问:
docker network create -d overlay tomcat-net
- 创建名为tomcat的服务,使用了刚才创建的覆盖网络:
docker service create --name tomcat \
--network tomcat-net \
-p 8080:8080 \
--replicas 3 \
tomcat:7.0.96-jdk8-openjdk
- 执行命令docker service ls查看当前所有服务:
[root@m0 ~]# docker service ls
ID NAME MODE REPLICAS IMAGE
kguawc4b5th4 tomcat replicated 3/3 tomcat:7.0.96-jdk8-openjdk
- 执行命令docker service ps tomcat查看名为tomcat的服务,可见三个容器分别部署在m0、m2、w1机器上:
[root@m0 ~]# docker service ps tomcat
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
n1gs9f1plce2 tomcat.1 tomcat:7.0.96-jdk8-openjdk w1 Running Running 19 minutes ago
q8jyg088ci21 tomcat.2 tomcat:7.0.96-jdk8-openjdk m2 Running Running 19 minutes ago
h9ww33dpw56m tomcat.3 tomcat:7.0.96-jdk8-openjdk m0 Running Running 19 minutes ago
- 执行命令docker service inspect --pretty tomcat查看名为tomcat的服务的详细信息(去掉--pretty可以看到更完整的):
[root@m0 ~]# docker service inspect --pretty tomcat
ID: kguawc4b5th4qlwlsv183qtai
Name: tomcat
Service Mode: Replicated
Replicas: 3
Placement:
UpdateConfig:
Parallelism: 1
On failure: pause
Max failure ratio: 0
ContainerSpec:
Image: tomcat:7.0.96-jdk8-openjdk@sha256:91eadffb59d9a35ada2d39fcd616a749ac580aa5e834499b7128f27be2e46623
Resources:
Networks: tomcat-net
Endpoint Mode: vip
Ports:
PublishedPort 8080
Protocol = tcp
TargetPort = 8080
打开浏览器,尝试访问m0、m1、m2、w0、w1这个五个机器的8080端口,都可以成功访问tomcat首页:
服务模式
- 服务模式一共有两种:Ingress和Host,如果不指定,则默认的是Ingress;
- Ingress模式下,到达Swarm任何节点的8080端口的流量,都会映射到任何服务副本的内部80端口,就算该节点上没有tomcat服务副本也会映射;
- Host模式下,仅在运行有容器副本的机器上开放端口,使用Host模式的命令如下:
docker service create --name tomcat \
--network tomcat-net \
--publish published=8080,target=8080,mode=host \
--replicas 3 \
tomcat:7.0.96-jdk8-openjdk
服务扩缩容
- 执行命令docker service scale tomcat=5将副本数从3调整为5:
[root@m0 ~]# docker service scale tomcat=5
tomcat scaled to 5
- 执行命令docker service ps tomcat查看名为tomcat的服务,可见每台机器上都分布了一个容器:
[root@m0 ~]# docker service ps tomcat
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
w32tjahze2fk tomcat.1 tomcat:7.0.96-jdk8-openjdk m2 Running Running 42 minutes ago
yj5czwwhrrsh tomcat.2 tomcat:7.0.96-jdk8-openjdk m0 Running Running 42 minutes ago
pq40995nbd0k tomcat.3 tomcat:7.0.96-jdk8-openjdk w1 Running Running 42 minutes ago
y1y6z1jczel1 tomcat.4 tomcat:7.0.96-jdk8-openjdk m1 Running Running about a minute ago
w0dcii8f79os tomcat.5 tomcat:7.0.96-jdk8-openjdk w0 Running Running about a minute ago
滚动升级
- 当前tomcat服务中,tomcat镜像的tag是7.0.96-jdk8-openjdk,我们来尝试升级到9.0.24-jdk11-openjdk,执行以下命令:
docker service update \
--image tomcat:9.0.24-jdk11-openjdk \
--update-parallelism 1 \
--update-delay 10s tomcat
上述命令有几处需要注意:
a. update-parallelism:每次更新的容器数量,这里设置为1,表示每一个容器升级成功后才去升级下一个;
b. update-delay:每一批升级成功后,升级下一批之前的等待时间,这里表示升级一个容器后等10秒再升级下一个;
- 在升级过程中