[RFC] build: add build tag to disable eBPF

[giuseppe]

we are using runc to read the cgroup configuration, if eBPF is enabled it pulls in the cilium/ebpf dependency that increases the binary size by ~1 MB.

[giuseppe]

@AkihiroSuda @kolyshkin what do you think about this flag?

[AkihiroSuda]

Sorry, NACK, as eBPF is a hard dependency for cgroup v2 (in the initial UserNS)

[AkihiroSuda]

For library use, the packages should be just split and refactored to eliminate eBPF deps

[AkihiroSuda]

NACK, please see my comments above

[giuseppe]

For library use, the packages should be just split and refactored to eliminate eBPF deps

how do you suggest splitting it?

[kolyshkin]

@giuseppe this is already solved last year in #3452 (in a way described by @AkihiroSuda above). So you can try using runc from HEAD and seeing if it helps with the bloat.

The only problem is, we haven't made a release having it yet. Working on it.

[giuseppe]

@giuseppe this is already solved last year in #3452 (in a way described by @AkihiroSuda above). So you can try using runc from HEAD and seeing if it helps with the bloat.

The only problem is, we haven't made a release having it yet. Working on it.

I've tried with the latest runc from HEAD but I still get the ebpf dependency, and as a result the podman binary is ~1MB bigger. I'll check better if I am doing anything wrong, but I cannot see any import of github.com/opencontainers/runc/libcontainer/cgroups/devices:

$ go mod why github.com/opencontainers/runc/libcontainer/cgroups/devices
# github.com/opencontainers/runc/libcontainer/cgroups/devices
(main module does not need package github.com/opencontainers/runc/libcontainer/cgroups/devices)

[giuseppe]

I'll close this PR and investigate better the proposed way

[giuseppe]

The only problem is, we haven't made a release having it yet. Working on it.

sadly the last release did not fix the issue I have reported. It is enough to pull github.com/opencontainers/runc/libcontainer/cgroups/fs and it will add the dependency on /devices and eBPF:

$ go mod why github.com/opencontainers/runc/libcontainer/cgroups/devices
# github.com/opencontainers/runc/libcontainer/cgroups/devices
github.com/containers/podman/v4/cmd/podman/containers
github.com/containers/common/pkg/cgroups
github.com/opencontainers/runc/libcontainer/cgroups/fs
github.com/opencontainers/runc/libcontainer/cgroups/devices