From 542d8fe95f66c0a3aabb9d964c260a0b3b9aaae8 Mon Sep 17 00:00:00 2001 From: Daniel J Walsh Date: Fri, 9 Nov 2018 11:22:44 -0500 Subject: Better document rootless containers Need to return an error pointing user in right direction if rootless podman fails, because of no /etc/subuid or /etc/subgid files. Also fix up man pages to better describe rootless podman. Signed-off-by: Daniel J Walsh --- docs/podman.1.md | 9 +++++---- pkg/rootless/rootless_linux.go | 3 +++ 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/docs/podman.1.md b/docs/podman.1.md index c66a9cf05..b7433d850 100644 --- a/docs/podman.1.md +++ b/docs/podman.1.md @@ -192,7 +192,7 @@ the exit codes follow the `chroot` standard, see below: When Podman runs in rootless mode, the file `$HOME/.config/containers/storage.conf` is also loaded. ## Rootless mode -Podman can also be used as non-root user. When podman runs in rootless mode, an user namespace is automatically created. +Podman can also be used as non-root user. When podman runs in rootless mode, a user namespace is automatically created for the user, defined in /etc/subuid and /etc/subgid. Containers created by a non-root user are not visible to other users and are not seen or managed by podman running as root. @@ -209,13 +209,14 @@ Or just add the content manually. $ echo USERNAME:10000:65536 >> /etc/subuid $ echo USERNAME:10000:65536 >> /etc/subgid +See the `subuid(5)` and `subgid(5)` man pages for more information. + Images are pulled under `XDG_DATA_HOME` when specified, otherwise in the home directory of the user under `.local/share/containers/storage`. -Currently it is not possible to create a network device, so rootless containers need to run in the host network namespace. If a rootless container creates a network namespace, -then only the loopback device will be available. +Currently the slirp4netns package is required to be installed to create a network device, otherwise rootless containers need to run in the network namespace of the host. ## SEE ALSO -`containers-mounts.conf(5)`, `containers-registries.conf(5)`, `containers-storage.conf(5)`, `crio(8)`, `libpod.conf(5)`, `oci-hooks(5)`, `policy.json(5)` +`containers-mounts.conf(5)`, `containers-registries.conf(5)`, `containers-storage.conf(5)`, `crio(8)`, `libpod.conf(5)`, `oci-hooks(5)`, `policy.json(5)`, `subuid(5)`, `subgid(5)`, `slirp4netns(1)` ## HISTORY Dec 2016, Originally compiled by Dan Walsh diff --git a/pkg/rootless/rootless_linux.go b/pkg/rootless/rootless_linux.go index 5c45f2694..ff8c8fe34 100644 --- a/pkg/rootless/rootless_linux.go +++ b/pkg/rootless/rootless_linux.go @@ -187,6 +187,9 @@ func BecomeRootInUserNS() (bool, int, error) { if username == "" { user, err := user.LookupId(fmt.Sprintf("%d", os.Getuid())) if err != nil && os.Getenv("PODMAN_ALLOW_SINGLE_ID_MAPPING_IN_USERNS") == "" { + if os.IsNotExist(err) { + return false, 0, errors.Wrapf(err, "/etc/subuid or /etc/subgid does not exist, see subuid/subgid man pages for information on these files") + } return false, 0, errors.Wrapf(err, "could not find user by UID nor USER env was set") } if err == nil { -- cgit v1.2.3-54-g00ecf