ceamac/slocker-lite
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Document the tap+relay veth fallback in the design doc

Browse Source 
Adds a dedicated section to docs/networking-design.md covering the
tap+relay fallback for veth-less kernels: the trigger (real target
device supports tun/tap but not veth), why tap can't 1:1 replace veth,
the confirmed design (two tap devices + a relay reusing the existing
bridge, replacing veth's earlier N-way-switch-daemon sketch once
bridge support was confirmed available), the four-commit
implementation sequence with what testing actually found (the fd-leak
deadlock, the reverted cgroup fix), and an honest writeup of the
unresolved gateway/outside-reachability gap.

README.md's -n/--network row now also flags that gap directly, next
to the existing NAT-hairpinning limitation note for -p.

This closes out the tap+relay fallback work for now: peer-to-peer
connectivity through it is solid and dev-verified; gateway/outside
reachability needs re-verification on the actual veth-less target
device before being relied on.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
This commit is contained in:
Viorel Munteanu
2026-08-30 16:36:43 +00:00
parent fd234124e1
commit 53b859b7bf
2 changed files with 113 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files
README.md
+1 -1
View File
@@ -92,7 +92,7 @@ slocker-lite -V|--version
| `--list-volumes` | List all named volumes (see `-v/--volume`) with their host directory. |
| `--delete-volume <name>` | Remove a named volume from the config. The host directory is left untouched. |
| `--delete-volume-full <name>` | Like `--delete-volume`, but also recursively deletes the volume's host directory. |
| `-n, --network <name>` | Create/manage a persistent named network: requires exactly one of `--extern` (a real Linux bridge in the host's own namespace, with NAT/forwarding set up so containers on it reach the host's real network) or `--intern` (a bridge inside its own dedicated, routeless namespace, only reachable by other containers on the same network). `--subnet <cidr>` overrides the auto-allocated IPv4 range (`10.168.0.0/24`, incrementing per network); `--no-ipv6` disables (and `--subnet6 <cidr>` overrides) the auto-allocated IPv6 range, on by default. `--no-veth` forces the tap+relay join fallback even on a kernel that supports veth (useful for testing that path; it's otherwise chosen automatically whenever the running kernel lacks veth support). With `--run`, instead joins `<name>` to the container as its own `eth<N>` interface with an address from the network's subnet; repeatable, no membership limit. Root-only for now. See [`docs/networking-design.md`](docs/networking-design.md). |
| `-n, --network <name>` | Create/manage a persistent named network: requires exactly one of `--extern` (a real Linux bridge in the host's own namespace, with NAT/forwarding set up so containers on it reach the host's real network) or `--intern` (a bridge inside its own dedicated, routeless namespace, only reachable by other containers on the same network). `--subnet <cidr>` overrides the auto-allocated IPv4 range (`10.168.0.0/24`, incrementing per network); `--no-ipv6` disables (and `--subnet6 <cidr>` overrides) the auto-allocated IPv6 range, on by default. `--no-veth` forces the tap+relay join fallback even on a kernel that supports veth (useful for testing that path; it's otherwise chosen automatically whenever the running kernel lacks veth support). With `--run`, instead joins `<name>` to the container as its own `eth<N>` interface with an address from the network's subnet; repeatable, no membership limit. Root-only for now. **Known gap**: on a network joined via the tap+relay fallback, peer-to-peer connectivity works, but reaching the network's own gateway (and thus the outside, for `extern`) does not yet — root cause unconfirmed, see [`docs/networking-design.md`](docs/networking-design.md). |
| `--list-networks` | List all named networks (see `-n/--network`) with their kind, IPv4 subnet, and IPv6 subnet (or `(no ipv6)`). |
| `--delete-network <name>` | Remove a named network from the config. |
| `-p, --port-forward [<network>:]<host-port>:<container-port>` | With `--run`, forward a TCP port from the host into the container. `<network>` is optional, defaulting to the container's sole `--extern` network (an error if it joined more than one without specifying). Repeatable. Reachable via the host's real, externally-facing IP; `localhost`/loopback access has a known NAT-hairpinning limitation (see [`docs/networking-design.md`](docs/networking-design.md)). |