Re:Linux 3.8 introduced unprivileged user namespaces [pdf]
by technofiend on Wednesday December 18, 2019 @12:41PM
(#21827255)
Kudos to Redhat for backporting the kernel 4 and package changes needed to RHEL 7 which is still on a version 3 Linux kernel. Rootless containers with podman was a technology preview in RHEL 7.6 and it's now supported in RHEL 7.7 [1].
There are some caveats - specifically copy-on-write filesystems aren't yet supported but Redhat says it's on the RHEL 7 roadmap. And you need a fresh of install 7.7 to get the right behavior out of the box, otherwise there are manual steps required for upgraded systems. Specifically stackoverflow examples should if there is a usermapping to unprivileged IDs and the user aliases or links docker to podman.
There are some caveats - specifically copy-on-write filesystems aren't yet supported but Redhat says it's on the RHEL 7 roadmap. And you need a fresh of install 7.7 to get the right behavior out of the box, otherwise there are manual steps required for upgraded systems. Specifically stackoverflow examples should if there is a usermapping to unprivileged IDs and the user aliases or links docker to podman.
[1] https://www.redhat.com/en/blog/three-new-container-capabilit...