weave/site/troubleshooting.md

title, layout

title	layout
Troubleshooting Weave	default

Troubleshooting

Make sure you are running the latest version - you can download it with

docker pull zettio/weave:latest

Check the weave container logs with

docker logs weave

A reasonable amount of information, and all errors, get logged there.

The log verbosity can be increased by supplying the -debug flag when launching weave. Be warned, this will log information on a per-packet basis, so can produce a lot of output.

Another useful debugging technique is to attach standard packet capture and analysis tools, such as tcpdump and wireshark, to the weave network bridge on the host.

One can ask a weave router for a status report or for a list of attached containers.

To stop weave, run

weave stop

Note that this leaves the local application container network intact; containers on the local host can continue to communicate, whereas communication with containers on different hosts, as well as service export/import, is disrupted but resumes when weave is relaunched.

To stop weave and completely remove all traces of the weave network on the local host, run

weave reset

Any running application containers will permanently lose connectivity with the weave network and have to be restarted in order to re-connect.

Status report

The command

weave status

reports on the current status of the weave router.

This produces output like:

weave router 0.7.0
Encryption off
Our name is 7a:f4:56:87:76:3b
Sniffing traffic on &{39 65535 ethwe ae:e3:07:9c:8c:d4 up|broadcast|multicast}
MACs:
ba:8c:b9:dc:e1:c9 -> 7a:f4:56:87:76:3b (2014-10-23 16:39:19.482338935 +0000 UTC)
ce:15:34:a9:b5:6d -> 7a:f4:56:87:76:3b (2014-10-23 16:39:28.257103595 +0000 UTC)
7a:61:a2:49:4b:91 -> 7a:f4:56:87:76:3b (2014-10-23 16:39:27.482970752 +0000 UTC)
9e:95:0c:54:8e:39 -> 7a:16:dd:5b:83:de (2014-10-23 16:39:28.795601325 +0000 UTC)
72:5f:a4:60:e5:ce -> 7a:16:dd:5b:83:de (2014-10-23 16:39:29.575995255 +0000 UTC)
Peers:
Peer 7a:16:dd:5b:83:de (v31) (UID 13151318985609435078)
   -> 7a:f4:56:87:76:3b [37.157.33.76:7195]
Peer 7a:f4:56:87:76:3b (v1) (UID 6913268221365110570)
   -> 7a:16:dd:5b:83:de [191.235.147.190:6783]
Routes:
unicast:
7a:f4:56:87:76:3b -> 00:00:00:00:00:00
7a:16:dd:5b:83:de -> 7a:16:dd:5b:83:de
broadcast:
7a:f4:56:87:76:3b -> [7a:16:dd:5b:83:de]
7a:16:dd:5b:83:de -> []
Reconnects:
192.168.32.1:6783 (next try at 2014-10-23 16:39:50.585932102 +0000 UTC)

The terms used here are explained further at how it works.

The 'Our name' line identifies the local weave router as a peer in the weave network.

The 'Sniffing traffic' line shows details of the virtual ethernet interface that weave is using to receive packets on the local machine.

The 'MACs' section lists all MAC addresses known to this router. These identify containers in the weave network, as well as points for host network integration. For each MAC the list shows the peer they reside on, and the time when the router last saw some traffic from that MAC. The router forgets addresses which are inactive for longer than 10 minutes.

The 'Peers' section lists all peers known to this router, including itself. Each peer is shown with its name, version number (incremented on each reconnect) and the UID. Then each line beginning -> shows another peer that it is connected to, with the IP address and port number of the connection. In the above example, the local router has connected to its peer using address 191.235.147.190:6783, and its peer sees the same connection as coming from 37.157.33.76:7195.

The 'Routes' section summarised the information for deciding how to route packets between peers, which is mostly of interest when the weave network is not fully connected. See the architecture documentation for a full explanation.

Finally, 'Reconnects' lists peers that this router is aware of, but is not currently connected to. Each line contains some information about whether it is attempting to connect or is waiting for a while before connecting again.

List attached containers

weave ps

Produces a list of all the containers running on this host that are connected to the weave network, like this:

b07565b06c53 ae:e3:07:9c:8c:d4
5245643870f1 ce:15:34:a9:b5:6d 10.0.5.1/24
e32a7d37a93a 7a:61:a2:49:4b:91 10.0.8.3/24
caa1d4ee2570 ba:8c:b9:dc:e1:c9 10.0.1.1/24 10.0.2.1/24

On each line are the container ID, its MAC address, then the list of IP address/routing prefix length (CIDR notation) assigned on the weave network.

Reboots

When a host reboots, docker's default behaviour is to restart any containers that were running. Since weave relies on special network configuration outside of the containers, the weave network will not function in this state.

To remedy this, stop and re-launch the weave container, and re-attach the application containers with weave attach.

For a more permanent solution, disable Docker's auto-restart feature and create appropriate startup scripts to launch weave and run application containers from your favourite process manager.