June 2019 - Podman - Podman List Archives

Setting up 2 containers
by Christoffer Reijer 29 Jun '19

29 Jun '19

This seems like a pretty basic use case but I cannot seem to find out how to do this: I want to create two containers, foo and bar, and have them talk to each other on ports that are not exposed to anything else. I used to do this by creating a docker network, my_network, that I attached my two containers to, and then I could access foo.my_network from the bar container. But how moving to RHEL 8 I have to port my code away from Docker and I can't figure out how to get my two containers to talk. It works fine on IP (10.88.0.10 and 10.88.0.11) but I would prefer to use the name since I don't trust the IP to be the same at every run. Any ideas?

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Including file system changes in container migration
by Adrian Reber 25 Jun '19

25 Jun '19

The current container migration implementation in Podman cannot handle changes to the file-system. If a container changes a file the recommendation is to mount that directory as a tmpfs and then the changed file will be correctly migrated to the destination system. If something changes a file in /tmp for example, following steps are currently necessary: # podman run -d --tmpfs /tmp <container> # podman container checkpoint -l -e /tmp/chkpt.tar.gz # scp /tmp/chkpt.tar.gz destination-host:/tmp On the destination host of the migration: # podman container restore -i /tmp/chkpt.tar.gz Files changed in /tmp in the container will also be in the restored container on the destination host, because CRIU automatically handles tmpfs directories. To make it easier for users to not have to mark all changed directories as --tmpfs I would like to include changed files in the checkpoint archive (/tmp/chkpt.tar.gz from my example). One possible implementation could use vendor/github.com/containers/storage/store.go: // Diff returns the tarstream which would specify the changes returned // by Changes. If options are passed in, they can override default // behaviors. Diff(from, to string, options *DiffOptions) (io.ReadCloser, error) This sounds exactly like what I need. I get a tarstream which I can embed into the checkpoint archive and which can then be used with ApplyDiff() before restoring the container. Does this sound like the right approach to also migrate file-system changes during container migration? Adrian

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Inter-container communication in pod
by Dominik Matis 19 Jun '19

19 Jun '19

Hi, I have a situation in which I have React app in container, which is exposed to port 3000 to be able to access it from host and I also have another container for Express API server, which is listening on port 8000, but I don't want it to be accessible from host. Is it somehow possible to run these two containers simultaneously in one pod and have exposed only port 3000, so we can see the page? Thanks for a reply. Best regards, Dominik Matis

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Question regarding volumes and permissions
by Eric Gustavsson 17 Jun '19

17 Jun '19

Hi all, I got a bit on an issue trying to spin up a container with a volume mounted to the container's /data directory. Got a related issue here but I believe I'm just missing out on something Podman specific https://github.com/dani-garcia/bitwarden_rs/issues/506 When I run this command and mount /bw-data to container's /data the bitwardenrs image can't write to it. podman run -d --user 1001 --name bitwarden -e [ROCKET_PORT=8080,ENABLE_DB_WAL=false] -v /home/spytec/Bitwarden/bw-data/:/data/ -p 8080:8080 bitwardenrs/server:latest Inside the container the /data directory is assigned to root, outside the container /bw-data has 0777 permissions and belong to myself (user 1001). Am I missing something? Thanks, Eric Gustavsson Associate Software Engineer Red Hat <https://www.redhat.com> <https://www.redhat.com>

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Podman Mailing List is Live!
by Tom Sweeney 13 Jun '19

13 Jun '19

Hi All, Duck Dequenes and Sanja Bonic were able to help Dan and I through the last hurdles to getting the list up and running appropriately. Many thanks to Ed Santiago who found a last minute issue with the setup that has since been corrected. So feel free to advertise the list as you wish. Send an email to: podman-join(a)lists.podman.io with the word "subscribe" in the title, or by going to https://lists.podman.io and scrolling to the bottom of that page to subscribe. Note: The Buildah mailing list will be moving from buildah(a)lists.podman.io to buildah(a)lists.buildah.io. There's still a few tweaks left there, please don't advertise that one ATM. Questions? Holler! Thanks all, t

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