docs(initrd): Add Podman usage in BuildKit connection error (#2201)

Reviewed-by: Alexander Jung <alex@unikraft.io>
Approved-by: Alexander Jung <alex@unikraft.io>

Author: nderjung

initrd/dockerfile.go

@@ -318,7 +318,12 @@ func (initrd *dockerfile) Build(ctx context.Context) (string, error) {
 			log.G(ctx).Warn("which you can do by running:")
 			log.G(ctx).Warn("")
 			log.G(ctx).Warn("  docker run --rm -d --name buildkit --privileged moby/buildkit:" + buildkitVersion)
-			log.G(ctx).Warn("  export KRAFTKIT_BUILDKIT_HOST=docker-container://buildkit")
+			log.G(ctx).Warn("")
+			log.G(ctx).Warn("Depending on your container runtime, you should connect to Buildkit via:")
+			log.G(ctx).Warn("")
+			log.G(ctx).Warn("  export KRAFTKIT_BUILDKIT_HOST=docker-container://buildkit # for docker")
+			log.G(ctx).Warn("or")
+			log.G(ctx).Warn("  export KRAFTKIT_BUILDKIT_HOST=podman-container://buildkit # for podman")
 			log.G(ctx).Warn("")
 			log.G(ctx).Warn("For more usage instructions visit: https://unikraft.org/buildkit")
 			log.G(ctx).Warn("")