Administrative Tasks

The following administrative tasks are discussed:

Configuring Weave Net to Start Automatically on Boot
Detecting and Reclaiming Lost IP Address Space
Manually Reclaiming Lost Address Space
Upgrading a Cluster
Resetting Persisted Data

Configuring Weave Net to Start Automatically on Boot

weave launch runs all of Weave Net’s containers with a Docker restart policy set to always. If you have launched Weave Net manually at least once and your system is configured to start Docker on boot, then Weave Net will start automatically on system restarts.

If you are aiming for a non-interactive installation, use systemd or a similar init system to launch Weave using the --no-restart flag after Docker has been started.

Detecting and Reclaiming Lost IP Address Space

The recommended method of removing a peer is to run weave reset on that peer before the underlying host is decommissioned or repurposed. This ensures that the portion of the IPAM allocation range assigned to the peer is released for reuse.

Under certain circumstances this operation may not be successful, or possible:

If the peer is partitioned from the rest of the network when weave reset is executed on it
If the underlying host is no longer available to execute weave reset due to a hardware failure or other unplanned termination (for example when using autoscaling with spot-instances that can be destroyed without notice)

In some cases you may already be aware of the problem, as you were unable to execute weave reset successfully or because you know through other channels that the host has died. In these cases you can proceed straight to Manually Reclaiming Lost Address Space.

However in some scenarios it may not be obvious that space has been lost, in which case you can check for it periodically with the following command on any peer:

weave status ipam

This command displays the peer names and nicknames, absolute quantity/percentage of allocation range managed by peer and also identifies the names of unreachable peers. If you are satisfied that the peer is truly gone, rather than temporarily unreachable due to a partition, you can reclaim their space manually.

Manually Reclaiming Address Space

When a peer dies unexpectedly the remaining peers will consider its address space to be unavailable even after it has remained unreachable for prolonged periods. There is no universally applicable time limit after which one of the remaining peers could decide unilaterally that it is safe to appropriate the space for itself, and so an administrative action is required to reclaim it.

The weave rmpeer command is provided to perform this task, and must be executed on one of the remaining peers. That peer will then take ownership of the freed address space.

Upgrading a Cluster

Protocol versioning and feature negotiation are employed in Weave Net to enable incremental rolling upgrades. Each major maintains the ability to speak to the preceding major release at a minimum, and connected peers only utilize features which both support.

The general upgrade procedure is as follows:

On each peer:

Stop the old Weave Net with weave stop (or systemctl stop weave if you’re using a systemd unit file)
Download the new Weave Net script and replace the existing one
Start the new Weave with weave launch <existing peer list> (or systemctl start weave if you’re using a systemd unit file)

To minimize downtime while the new script is pulling the new container images:

Download the new Weave Net script to a temporary location, for example, /path/to/new/weave
Pull the new images with /path/to/new/weave setup
Stop the old Weave Net with weave stop (or systemctl stop weave if you’re using a systemd unit file)
Replace the existing script with the new one
Start the new Weave Net with weave launch <existing peer list> (or systemctl start weave if you’re using a systemd unit file)

Note: Always check the Release Notes for specific versions in case there are any special caveats or deviations from the standard procedure.

Resetting Persisted Data

Weave Net persists information in a data volume container named weavedb. If you wish to start from a completely clean slate (for example to withdraw a peer from one network and join it to another) you can issue the following command:

weave reset

See Also