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Get easy access to container files via procfs
Read container files via procfs:
$ ps fax
[...]
24320 ? Sl 1:26 /usr/sbin/containerd-shim-runc-v2 [...]
24341 pts/0 Ss+ 0:00 \_ /bin/bash /entry.sh
[...]
$ cat /proc/24341/root/entry.sh
#!/bin/bash
set -e
supervisord -c /etc/supervisord.conf
$ cat /proc/24341/root/etc/hostname
somecontainer
When inspecting containers, such as during a white-box audit, it is often helpful to quickly inspect files within a container. Instead of entering the container or copying the file in question, you can use the procfs on the host side to access any file.
The trick is that the /proc//root symlink translates into the container’s mount namespace. This means reading from /proc//root/foo will access /foo inside the container’s mount namespace.
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