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Dynamically Attaching and Detaching Applications |
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Documentation |
When containers may not know the network to which they will be attached, Weave Net enables you to dynamically attach and detach containers to and from a given network, even when a container is already running.
To illustrate...
host1$ C=$(docker run -e WEAVE_CIDR=none -dti weaveworks/ubuntu)
host1$ weave attach $C
10.2.1.3
where,
C=$(docker run -e WEAVE_CIDR=none -dti weaveworks/ubuntu)
starts a container and assigns its ID to a variableweave attach
– the Weave Net command to attach to the specified container10.2.1.3
- the allocated IP address output byweave attach
, in this case in the default subnet
Note If you are using the Weave Docker API proxy, it will have modified
DOCKER_HOST
to point to the proxy and therefore you will have to pass-e WEAVE_CIDR=none
to start a container that doesn't get automatically attached to the weave network for the purposes of this example.
A container can be detached from a subnet, by using the weave detach
command:
host1$ weave detach $C
10.2.1.3
You can also detach a container from one network and then attach it to a different one:
host1$ weave detach net:default $C
10.2.1.3
host1$ weave attach net:10.2.2.0/24 $C
10.2.2.3
or, attach a container to multiple application networks, effectively sharing the same container between applications:
host1$ weave attach net:default
10.2.1.3
host1$ weave attach net:10.2.2.0/24
10.2.2.3
Finally, multiple addresses can be attached or detached using a single command:
host1$ weave attach net:default net:10.2.2.0/24 net:10.2.3.0/24 $C
10.2.1.3 10.2.2.3 10.2.3.1
host1$ weave detach net:default net:10.2.2.0/24 net:10.2.3.0/24 $C
10.2.1.3 10.2.2.3 10.2.3.1
Important! Any addresses that were dynamically attached will not be re-attached if the container restarts.
See Also