To connect containers across untrusted networks, Weave Net peers can be instructed to encrypt traffic by supplying a --password option or by using the WEAVE_PASSWORD environment variable during weave launch.

For example:

host1$ weave launch --password wfvAwt7sj


host1$ export WEAVE_PASSWORD=wfvAwt7sj
host1$ weave launch

NOTE: The command line option takes precedence over the environment variable.

To avoid leaking your password via the kernel process table or your shell history, we recommend you store it in a file and capture it in a shell variable prior to launching weave: export WEAVE_PASSWORD=$(cat /path/to/password-file)

To guard against dictionary attacks, the password needs to be reasonably strong, with at least 50 bits of entropy. An easy way to generate a random password that satisfies this requirement is:

< /dev/urandom tr -dc A-Za-z0-9 | head -c9 ; echo

The same password must be specified for all Weave Net peers, by default both control and data plane traffic will then use authenticated encryption.

As an optimization, you can selectively disable data plane encryption if some of your peers are co-located in a trusted network, for example within the boundary of your own data center. List these networks using the --trusted-subnets argument with weave launch:

weave launch --password wfvAwt7sj --trusted-subnets,

If both peers at the end of a connection consider the other to be in the same trusted subnet, Weave Net attempts to establish non-encrypted connectivity. Otherwise communication is encrypted which imposes overheads.

Configured trusted subnets are shown in weave status.

Be aware that:

  • Containers will be able to access the router REST API if fast datapath is disabled. You can prevent this by setting: icc=false.
  • Containers are able to access the router control and data plane ports, but this can be mitigated by enabling encryption.

See Also