kubespray/docs/weave.md

# Weave

Weave 2.0.1 is supported by kubespray

Weave uses [**consensus**](https://www.weave.works/docs/net/latest/ipam/##consensus) mode (default mode) and [**seed**](https://www.weave.works/docs/net/latest/ipam/#seed) mode.

`Consensus` mode is best to use on static size cluster and `seed` mode is best to use on dynamic size cluster

Weave encryption is supported for all communication

* To use Weave encryption, specify a strong password (if no password, no encryption)

```ShellSession
# In file ./inventory/sample/group_vars/k8s-cluster.yml
weave_password: EnterPasswordHere
```

This password is used to set an environment variable inside weave container.

Weave is deployed by kubespray using a daemonSet

* Check the status of Weave containers

```ShellSession
# From client
kubectl -n kube-system get pods | grep weave
# output
weave-net-50wd2                       2/2       Running   0          2m
weave-net-js9rb                       2/2       Running   0          2m
```

There must be as many pods as nodes (here kubernetes have 2 nodes so there are 2 weave pods).

* Check status of weave (connection,encryption ...) for each node

```ShellSession
# On nodes
curl http://127.0.0.1:6784/status
# output on node1
Version: 2.0.1 (up to date; next check at 2017/08/01 13:51:34)

        Service: router
       Protocol: weave 1..2
           Name: fa:16:3e:b3:d6:b2(node1)
     Encryption: enabled
  PeerDiscovery: enabled
        Targets: 2
    Connections: 2 (1 established, 1 failed)
          Peers: 2 (with 2 established connections)
 TrustedSubnets: none

        Service: ipam
         Status: ready
          Range: 10.233.64.0/18
  DefaultSubnet: 10.233.64.0/18
```

* Check parameters of weave for each node

```ShellSession
# On nodes
ps -aux | grep weaver
# output on node1 (here its use seed mode)
root      8559  0.2  3.0 365280 62700 ?        Sl   08:25   0:00 /home/weave/weaver --name=fa:16:3e:b3:d6:b2 --port=6783 --datapath=datapath --host-root=/host --http-addr=127.0.0.1:6784 --status-addr=0.0.0.0:6782 --docker-api= --no-dns --db-prefix=/weavedb/weave-net --ipalloc-range=10.233.64.0/18 --nickname=node1 --ipalloc-init seed=fa:16:3e:b3:d6:b2,fa:16:3e:f0:50:53 --conn-limit=30 --expect-npc 192.168.208.28 192.168.208.19
```

## Consensus mode (default mode)

This mode is best to use on static size cluster

### Seed mode

This mode is best to use on dynamic size cluster

The seed mode also allows multi-clouds and hybrid on-premise/cloud clusters deployment.

* Switch from consensus mode to seed/Observation mode

See [weave ipam documentation](https://www.weave.works/docs/net/latest/tasks/ipam/ipam/) and use `weave_extra_args` to enable.