[lxc-users] LXD share /var/lib/mysql from host to container and map user/group

[Andrey Repin]

Greetings, Tony P!

> What's the correct way to share the mysql/mariadb data dir of the host
> system to a container and map the permissions correctly?

There's no correct way to *share* the database directory.
Database engine simply do not expect the shared locks in the slightest.

> I have been
> struggling with this for a couple of days. I'm sorry if this question has
> been asked before, but I have searched thoroughly and not been able to find
> the solution yet. Basically what I have done so far:


> Install mariadb-server on both host and container and:


> $ printf "lxd:$(id -u mysql):1\nroot:$(id -u mysql):1\n" | sudo tee -a /etc/subuid
> $ printf "lxd:$(id -g mysql):1\nroot:$(id -g mysql):1\n" | sudo tee -a /etc/subgid
> $ sudo systemctl restart lxd
> $ printf "uid $(id -u mysql) 1000\ngid $(id -g mysql) 1000" | lxc config set $CONTAINER_NAME raw.idmap -
> $ lxc restart $CONTAINER_NAME
> $ sudo lxc config device add $CONTAINER_NAME mysql disk
> source=/var/lib/mysql path=/var/lib/mysql
> Unfortunately, this breaks the container and prevents it from starting since the mapping isn't allowed.


> $ sudo lxc info --show-log ub1804x64-3


> Name: ub1804x64-3
> Remote: unix://
> Architecture: x86_64
> Created: 2018/07/09 15:30 UTC
> Status: Stopped
> Type: persistent
> Profiles: default


> Log:


> lxc ub1804x64-3 20180709154554.682 ERROR    lxc_conf -
> conf.c:lxc_map_ids:2919 - newuidmap failed to write mapping "newuidmap: uid
> range [1000-1001) -> [114-115) not allowed": newuidmap 6725 0 100000 1000 1000 114 1 1001 101001 64535
> lxc ub1804x64-3 20180709154554.682 ERROR    lxc_start -
> start.c:lxc_spawn:1661 - Failed to set up id mapping.
> lxc ub1804x64-3 20180709154554.755 WARN     lxc_network -
> network.c:lxc_delete_network_priv:2607 - Failed to remove interface
> "veth38DOB9" from "lxdbr0": Invalid argument
> lxc ub1804x64-3 20180709154554.755 ERROR    lxc_container -
> lxccontainer.c:wait_on_daemonized_start:834 - Received container state "ABORTING" instead of "RUNNING"
> lxc ub1804x64-3 20180709154554.756 ERROR    lxc_start -
> start.c:__lxc_start:1887 - Failed to spawn container "ub1804x64-3"
> lxc 20180709154554.775 WARN     lxc_commands -
> commands.c:lxc_cmd_rsp_recv:130 - Connection reset by peer - Failed to
> receive response for command "get_state"
> I'm basically following this article
> (https://stgraber.org/2017/06/15/custom-user-mappings-in-lxd-containers/)
> written by Stéphane Graber (the super awesome primary LXD developer) to
> achieve this. I'll admit that I don't fully understand what's going on here,
> if someone could help me understand my mistake a bit better, I'd really
> appreciate it. I have a feeling I have the range wrong (1000?). I previously
> attempted doing the same by manually adding the mysql user/group and trying
> to map those (instead of installing mysql), but that also didn't work out
> (Same error). This is what I tried before trying the mapping):


> $ sudo groupadd mysql
> $ sudo useradd -r -g mysql mysql


> I also tried with: 
> $ printf "both $(id -u mysql) $(id -u mysql)" | lxc config set $CONTAINER_NAME raw.idmap -


> Then the error I get is:


> $ sudo lxc info --show-log tmp3


> Name: tmp3
> Remote: unix://
> Architecture: x86_64
> Created: 2018/07/09 20:32 UTC
> Status: Stopped
> Type: persistent
> Profiles: default


> Log:


> lxc tmp3 20180709204423.805 ERROR    lxc_conf - conf.c:lxc_map_ids:2919 -
> newgidmap failed to write mapping "newgidmap: gid range [114-115) ->
> [114-115) not allowed": newgidmap 30081 114 114 1 0 100000 114 115 100115 65421
> lxc tmp3 20180709204423.805 ERROR    lxc_start - start.c:lxc_spawn:1661 - Failed to set up id mapping.
> lxc tmp3 20180709204423.876 WARN     lxc_network -
> network.c:lxc_delete_network_priv:2607 - Failed to remove interface
> "vethYL869L" from "lxdbr0": Invalid argument
> lxc tmp3 20180709204423.876 ERROR    lxc_container -
> lxccontainer.c:wait_on_daemonized_start:834 - Received container state "ABORTING" instead of "RUNNING"
> lxc tmp3 20180709204423.877 ERROR    lxc_start - start.c:__lxc_start:1887 - Failed to spawn container "tmp3"
> lxc 20180709204423.897 WARN     lxc_commands -
> commands.c:lxc_cmd_rsp_recv:130 - Connection reset by peer - Failed to
> receive response for command "get_state"




> I'm using LXD 3.0.1 running on host Ubuntu 18.04 amd64 and testing with a Ubuntu 18.04 amd64 container


> Thanks for your help in advance!!



-- 
With best regards,
Andrey Repin
Tuesday, July 10, 2018 0:11:53

Sorry for my terrible english...