Solve the communication between multiple Docker host containers

background

In the process of learning to deploy the elasticsearch cluster, the docker deployment method is adopted. Containers in a single docker host can communicate with each other, but elasticsearch requires more resources, generally one host and one node. So I cloned two virtual machines to simulate multi-host docker deployment in the production environment.

accident scene

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completed handshake with [{es01}{UnmdQLEwT-SK16zE4VTUpw}{ywZQUGfpSw6Rg73ox4dmsQ}{es01}{172.19.0.2}{172.19.0.2:9301}{cdfhilmrstw}] at [192.168.0.226:9301] but followup connection to [172.19.0.2:9301] failed

solution one

In the host, add the network segment of the docker container on the other host to the routing table.

Existing host A 192.168.0.226, host B 192.168.0.227
Modify the network segment used by the docker container on host A to 10.19.0.0/24, and host B remains the default network segment 172.19.0.0/24

temporary plan

Add routing table to host A

sudo route add -net 172.19.0.0 netmask 255.255.0.0 gw 192.168.0.227

Add routing table to host B

sudo route add -net 10.19.0.0 netmask 255.255.0.0 gw 192.168.0.226

The route added in this way will be lost after the network card is restarted.

permanent program

In /etc/init.d/network, there are the following scripts

# Add non interface-specific static-routes.
if [ -f /etc/sysconfig/static-routes ]; then
   if [ -x /sbin/route ]; then
      grep "^any" /etc/sysconfig/static-routes | while read ignore args ; do
      /sbin/route add -$args
         done
        else
            net_log $"Legacy static-route support not available: /sbin/route not found"
        fi
   fi

It means that if there is /etc/sysconfig/static-routes, it will filter out the execution route add at the beginning of any, which is equivalent to manually adding routes in the temporary solution. Special attention: the script will have its own - after the
route add, and the net after any Or there is no need to add -
A host in front of the host

sudo vim /etc/sysconfig/static-routes

Add the following

any net 172.19.0.0 netmask 255.255.0.0 gw 192.168.0.227

B host

sudo vim /etc/sysconfig/static-routes

Add the following

any net 10.19.0.0 netmask 255.255.0.0 gw 192.168.0.226

Then restart the host

sudo reboot

or restart the network card

sudo systemctl restart network

At this point, the containers in hosts A and B can access each other.
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solution two

Use Docker's overlay network to solve cross-host communication. If you only start with a container, you need to add –attachable to create an overlay network. Detailed explanation about the use of overlay network