Disk quota for Docker Containers

General Discussions General
1

We run database like postgres,mysql within Docker Containers. What is the best way to assign quotas to the volumes for the same.

  1. Via the host using setquota and mapping to a userid
  2. Using a volume driver which can talk to Block storages like Cinder or AWS Block Storage.
2

I’m not sure if this will help your use case, but docker run does have some knobs you can turn (flags) to control access to devices and block IO:

--blkio-weight                  Block IO (relative weight), between 10 and 1000
--blkio-weight-device=[]        Block IO weight (relative device weight)
....
--device=[]                     Add a host device to the container
--device-read-bps=[]            Limit read rate (bytes per second) from a device
--device-read-iops=[]           Limit read rate (IO per second) from a device
--device-write-bps=[]           Limit write rate (bytes per second) to a device
--device-write-iops=[]          Limit write rate (IO per second) to a device
3

We are trying the uid concept for limiting disk quotas. Since Swarm is the scheduler we use, the way I am trying to tackle is that having a mapping file of uid at swarm server level, and use constraints at the docker daemon level to let swarm choose containers of a specifc UID end up going to the node and thereby quota gets applied.Thoughts/Suggestions?

4

I don’t understand. Could you explain more about what you are trying to accomplish, or point me to a link which explains this concept?

5

Hi Nathan,
We assign user ids to the containers. And each userid(uid) has a quota of disk on host.
As Swarm level we maintain a mapping of userids to the name of the docker image we want to run on a particular host with quota applied.
Then we use constraints at the docker daemon level (using node=the userids),so that swarm spins the containers for the specific user id on the host on which the quotas are defined for that user id.
Regards
Shashank