9. Routingmesh service communication between clusters

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establish overlay gateway

docker network create -d overlay demo

docker network ls
NETWORK ID          NAME                  DRIVER              SCOPE
7a511becede2        bridge                bridge              local
im7c34k0bfxh        demo                  overlay             swarm
37856c9de79d        docker_gwbridge       bridge              local
c438996bf1e8        host                  host                local
idnr3c47eum5        ingress               overlay             swarm
a785589db128        lb-scale_default      bridge              local
14865f2115c6        none                  null                local
e9bba04074f1        wordpress_my-bridge   bridge              local

establish Service Use network by overlay

 

As shown in the figure above , We have three applications , Two service One client. They may be deployed in the same worker node On , It may also be deployed separately . The three applications in the picture above , At the same time, it is deployed in 127.0.0.11 On this node .client Want to visit service application , Can pass ip+ The form of the port number , It can also be accessed by application name . How to do it ？docker engine There's one in it DNS service , It sorts out the names of all the applications with IP Address mapping , however Docker DNS Generated and stored in the service IP Address , Not the container where the application is located IP Address , Applications are deployed in 127.0.0.11 nodes , But we see that DNS Stored in ip The address is 10.0.3/4/5, This is virtual IP,VIP. Because the container address of the deployed application changes due to downtime or capacity expansion ,DNS Assign an application a virtual IP, This virtual IP It won't change . So the application is virtual IP Visit each other , Re pass LVS To achieve the .

nslookup www.baidu.com/service name

You can check the domain name corresponding to ip Address , If the domain name is deployed in a cluster , It 's load balanced , It will also show multiple ip Address .

1. When we deploy applications in containers , You need to specify network,network Must be overlay Network protocol , It looks like swarm Of DNS Will use vip To communicate with each other .

2. If the deployed application is bound to an interface , Even if it's deployed on a node , You can also visit swarm This port number of other nodes in the , To access the app .