81 lines
3.1 KiB
Markdown
81 lines
3.1 KiB
Markdown
# Rootless mode (Experimental)
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Requirements:
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- runc `ecd55a4135e0a26de884ce436442914f945b1e76` (May 30, 2018) or later
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- Some distros such as Debian (excluding Ubuntu) and Arch Linux require `echo 1 > /proc/sys/kernel/unprivileged_userns_clone`
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- `newuidmap` and `newgidmap` need to be installed on the host. These commands are provided by the `uidmap` package.
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- `/etc/subuid` and `/etc/subgid` should contain >= 65536 sub-IDs. e.g. `penguin:231072:65536`.
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- To run in a Docker container with non-root `USER`, `docker run --privileged` is still required. See also Jessie's blog: https://blog.jessfraz.com/post/building-container-images-securely-on-kubernetes/
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## Set up
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Setting up rootless mode also requires some bothersome steps as follows, but you can also use [`rootlesskit`](https://github.com/rootless-containers/rootlesskit) for automating these steps.
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### Terminal 1:
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```
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$ unshare -U -m
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unshared$ echo $$ > /tmp/pid
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```
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Unsharing mountns (and userns) is required for mounting filesystems without real root privileges.
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### Terminal 2:
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```
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$ id -u
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1001
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$ grep $(whoami) /etc/subuid
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penguin:231072:65536
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$ grep $(whoami) /etc/subgid
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penguin:231072:65536
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$ newuidmap $(cat /tmp/pid) 0 1001 1 1 231072 65536
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$ newgidmap $(cat /tmp/pid) 0 1001 1 1 231072 65536
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```
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### Terminal 1:
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```
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unshared# buildkitd
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```
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* The data dir will be set to `/home/penguin/.local/share/buildkit`
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* The address will be set to `unix:///run/user/1001/buildkit/buildkitd.sock`
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* `overlayfs` snapshotter is not supported except Ubuntu-flavored kernel: http://kernel.ubuntu.com/git/ubuntu/ubuntu-artful.git/commit/fs/overlayfs?h=Ubuntu-4.13.0-25.29&id=0a414bdc3d01f3b61ed86cfe3ce8b63a9240eba7
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* containerd worker is not supported ( pending PR: https://github.com/containerd/containerd/pull/2006 )
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* Network namespace is not used at the moment.
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### Terminal 2:
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```
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$ go get ./examples/build-using-dockerfile
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$ build-using-dockerfile --buildkit-addr unix:///run/user/1001/buildkit/buildkitd.sock -t foo /path/to/somewhere
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```
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## Set up (using a container)
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```
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$ docker build -t buildkit-rootless --target rootless -f hack/dockerfiles/test.Dockerfile .
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$ docker run --name buildkitd -d --privileged -p 1234:1234 buildkit-rootless --addr tcp://0.0.0.0:1234
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```
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`docker run` requires `--privileged` but the BuildKit daemon is executed as a normal user.
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See [`moby/moby#36597`](https://github.com/moby/moby/issues/36597, [`kubernetes/community#1934`](https://github.com/kubernetes/community/pull/1934) and [Jess's blog](https://blog.jessfraz.com/post/building-container-images-securely-on-kubernetes/) for the ongoing work to remove this requirement
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```
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$ docker exec buildkitd id
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uid=1000(user) gid=1000(user)
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$ docker exec buildkitd ps aux
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PID USER TIME COMMAND
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1 user 0:00 rootlesskit buildkitd --addr tcp://0.0.0.0:1234
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13 user 0:00 /proc/self/exe buildkitd --addr tcp://0.0.0.0:1234
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21 user 0:00 buildkitd --addr tcp://0.0.0.0:1234
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29 user 0:00 ps aux
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```
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```
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$ go get ./examples/build-using-dockerfile
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$ build-using-dockerfile --buildkit-addr tcp://127.0.0.1:1234 -t foo /path/to/somewhere
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```
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