Docker-学习总结（三剑客之Docker-swarm实践补充）

docker-swarm实践补充

服务自定义网络

Overlay是在传统网络上虚拟出一个虚拟网络来，传统网络不需要在做任何适配,这样物理层网络只对应物理层的计算（物理机、虚拟化层管理网），虚拟的网络只对应虚拟计算（虚拟机的业务IP）
VXLAN（Virtual eXtensible LAN）技术是当前最为主流的Overlay标准

1. Docker-swarm通常会在Docker自定义网络中，生成一个名称为ingress，网络驱动为overlay的网络模型，是swarm集群默认网络

[root@node1 ~]# docker network ls
NETWORK ID          NAME                DRIVER              SCOPE
3188fafd36fc        bridge              bridge              local
53ab6074c35d        docker_gwbridge     bridge              local
6371ab551939        host                host                local
ibd2iclozugf        ingress             overlay             swarm
275cc8b2d5cb        none                null                local

2. 自定义一个overlay的网络模型，名称为web_net

[root@node1 ~]# docker volume create --name my_volume
my_volume
[root@node1 ~]# docker network create -d overlay web_net
43buc1z36f1u72l871qjtgs88
[root@node1 ~]# docker network ls
NETWORK ID          NAME                DRIVER              SCOPE
3188fafd36fc        bridge              bridge              local
53ab6074c35d        docker_gwbridge     bridge              local
6371ab551939        host                host                local
ibd2iclozugf        ingress             overlay             swarm
275cc8b2d5cb        none                null                local
43buc1z36f1u        web_net             overlay             swarm

3. 创建服务使用自定义网络web_net

[root@node1 ~]# docker service create -p 80:80 --replicas 3 --name web_cluster --network web_net nginx
image nginx:latest could not be accessed on a registry to record
its digest. Each node will access nginx:latest independently,
possibly leading to different nodes running different
versions of the image.

ca9dke38d3vhpzyaoszig17yi
overall progress: 3 out of 3 tasks
1/3: running
2/3: running
3/3: running
verify: Service converged

4. 查看服务使用的网络信息

[root@node1 ~]# docker service ps web_cluster
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE                    ERROR               PORTS
3mjcen0t2svm        web_cluster.1       nginx:latest        node2               Running             Running 7 minutes ago
z59dmy0n2kzb        web_cluster.2       nginx:latest        node1               Running             Running 7 minutes ago
icdhyriarvbf        web_cluster.3       nginx:latest        node3               Running             Running less than a second ago**
#查看服务中运行在本机的容器ID，ID为z59dmy0n2kzb
[root@node1 ~]# docker inspect z59dmy0n2kzb |grep -A 10 web_net
                        "Name": "web_net",
                        "Labels": {},
                        "DriverConfiguration": {
                            "Name": "overlay"
                        },
                        "IPAMOptions": {
                            "Driver": {
                                "Name": "default"
                            }
                        },
                        "Scope": "swarm"

#可以看出容器使用的是自定义网络web_net，驱动模式是overlay

服务挂载自定义数据卷

通过挂载数据卷，统一管理数据

1. 自定义数据卷，定义数据卷前，先清除没用的数据卷

[root@node1 _data]# docker volume prune
WARNING! This will remove all local volumes not used by at least one container.
Are you sure you want to continue? [y/N] y
Total reclaimed space: 0B
[root@node1 _data]# docker volume ls
DRIVER              VOLUME NAME
[root@node1 volumes]# docker volume create --name web_data
web_data

2. 挂载数据卷在已有服务上

[root@node1 volumes]# docker service update --mount-add type=volume,src=web_data,dst=/usr/share/nginx/html web_cluster
web_cluster
overall progress: 3 out of 3 tasks
1/3: running
2/3: running
3/3: running
verify: Service converged
#将数据卷改在到发布目录上，由于使用的是volume，可将容器目录内的内容复制在指定卷目录中

3. 修改访问页面

[root@node1 volumes]# docker volume inspect web_data
[
    {
        "CreatedAt": "2020-02-15T13:40:36-05:00",
        "Driver": "local",
        "Labels": {},
        "Mountpoint": "/var/lib/docker/volumes/web_data/_data",
        "Name": "web_data",
        "Options": {},
        "Scope": "local"
    }
]
[root@node1 volumes]# cd /var/lib/docker/volumes/web_data/_data
[root@node1 _data]# ls
50x.html  index.html
[root@node1 _data]# echo hello  > index.html

4. 测试结果

[root@node1 _data]# for i in {1..10};do curl 192.168.27.11;done
hello
hello
hello
hello
hello
hello
hello
hello
hello
hello
#服务使用了统一的卷，修改了内容，访问变了