On Tue, Jan 26, 2016 at 03:16:22PM -0000, Martin Pitt wrote:
> Public bug reported:
>
> When running autopkgtests in remote containers (necessary for moving
> armhf autopkgtesting into the cloud) there is quite a noticeable
> overhead. Running lxc exec with a no-op locally takes almost no time:
>
> ubuntu@lxd-armhf2:~$ time lxc exec x1 whoami
> root
>
> real 0m0.076s
> user 0m0.010s
> sys 0m0.000s
>
> But running this from a remote instance consistently has some 2.5 to 3.5
> s overhead:
>
> ubuntu@lxd-controller:~$ lxc launch armhf2:cloud/xenial/armhf armhf2:x1
> ubuntu@lxd-controller:~$ time lxc exec --debug armhf2:x1 whoami </dev/null
> DBUG[01-26|15:08:20] Posting
> {"command":["whoami"],"environment":{"HOME":"/root","TERM":"screen","USER":"root"},"interactive":false,"wait-for-websocket":true}
> to https://10.43.42.59:8443/1.0/containers/x1/exec
> DBUG[01-26|15:08:21] Raw response:
> {"type":"async","status":"OK","status_code":100,"operation":"/1.0/operations/d183dcc6-5e94-43eb-9df8-35c963e8f2be","resources":null,"metadata":{"fds":{"0":"c10a5a34c84bfe86bdd4bc35c6a94349874b880ffb62a5709d01f15b97d92410","1":"fa77b9e2909863bb07247bf726223e46d8bf362284bd1cf74221e23cccc94885","2":"58337bcca5403e942a1f77f6acd899b6db9ab980ad8bfbef1cfea9470d52eae1","control":"0d55d71f9f8ebad1b8538f1c6538f86d1b973c1b368a1805af5b471baa9bc5b8"}}}
>
> root
> DBUG[01-26|15:08:23] Got error getting next reader websocket: close 1000 ,
> &{%!s(*os.file=&{1 /dev/stdout <nil>})}
> DBUG[01-26|15:08:23] Got error getting next reader websocket: close 1000 ,
> &{%!s(*os.file=&{2 /dev/stderr <nil>})}
> DBUG[01-26|15:08:23] 1.0/operations/d183dcc6-5e94-43eb-9df8-35c963e8f2be/wait
> DBUG[01-26|15:08:24] Raw response:
> {"type":"sync","status":"Success","status_code":200,"metadata":{"created_at":"2016-01-26T15:08:21.388232Z","updated_at":"2016-01-26T15:08:23.814687Z","status":"Success","status_code":200,"resources":null,"metadata":{"return":0},"may_cancel":false}}
>
> real 0m3.463s
> user 0m0.177s
> sys 0m0.021s
>
> ubuntu@lxd-controller:~$ lxc remote list
> [...]
> | armhf2 | https://10.43.42.59:8443 | NO |
> [...]
>
> I suppose this is due to the overhead of https://, establishing a new
> connection every time etc. openssh has some "connection sharing" feature
> which avoids the overhead of the initial negotiation and authentication.
> This is rather complex, so maybe not something that we have in LXD, but
> are there some tweaks to speed this up? E. g. switching off SSL, or
> switching off authentication (I trust these boxes, and they are
> firewalled rather tightly).
How about forwarding with socat? untested:
socat TCP-LISTEN:8443,fork UNIX-CLIENT:/var/lib/lxd/unix.socket
and on the other host:
socat UNIX-CONNECT:/tmp/unix.socket TCP:10.0.0.1:8443 # or whatever your
IP is
then,
LXD_DIR=/tmp lxc list
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https://bugs.launchpad.net/bugs/1538174
Title:
ways to speed up overhead of "lxc exec" on remote containers
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