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v0.19.0

This page mirrors the GitHub release, which also includes the full list of commits.

This release brings easier debugging of failed deploys, new troubleshooting commands (uc machine logs and uc machine rtt), and a nightly release channel.

Read on for the full list of changes and upgrade instructions.

Show logs from a failed deploy​

Changes: 8afe523, 303c8e4, 56a54ab

When uc deploy fails because a pre-deploy hook failed or a new container couldn't become healthy, it now prints the last 10 (configurable) log lines from the failed container.

This is a quality-of-life improvement that saves you from running a follow-up uc logs to figure out what went wrong.

Screenshot 2026-04-24 at 2 01 22 pm

See Failed container logs for more details.

Filter service logs by container​

Change: 2045819

uc logs now accepts a SERVICE/CONTAINER form where CONTAINER is a container name, full ID, or unique ID prefix. This is handy when one replica of a service is misbehaving and you want to look at it without the noise from the others:

uc logs web/2f60
# Mix and match
uc logs api/61d57fd3428f web/2f60 db

Stream machine logs​

⚠️ This requires both uc and the daemon to be upgraded to v0.19.0

PRs: #282, #283. Thanks to @miekg for the contribution ❤️

You can now stream logs from the systemd services that run Uncloud itself on remote machines using the new uc machine logs command. It covers three main services:

  • uncloud - the Uncloud daemon
  • uncloud-corrosion - the Corrosion service providing the distributed cluster store
  • docker - the Docker daemon

For example, stream the Uncloud daemon logs from all machines with:

uc machine logs -f uncloud

This is useful for troubleshooting Uncloud operations without having to SSH into every machine and run journalctl yourself.

See uc machine logs for more details and examples.

Round-trip time between machines​

⚠️ This requires both uc and the daemon to be upgraded to v0.19.0

PR: #226. Thanks to @jabr for the contribution ❤️

The new uc machine rtt command shows the round-trip time between every pair of machines in the cluster. This gives you a real-time view of how the mesh network is performing without needing to run manual ping tests.

The data is collected from Corrosion's gossip protocol, which samples latency between peers as part of its normal operation.

$ uc machine rtt
MACHINE     PEER        MEDIAN   STDDEV
machine-1   machine-2   140ms    ±19.4ms
machine-1   machine-3   39ms     ±1.1ms
machine-2   machine-1   168ms    ±18.5ms
machine-2   machine-3   203ms    ±42.3ms
machine-3   machine-1   40ms     ±2.0ms
machine-3   machine-2   158ms    ±15.2ms

A new RTT column has also been added to uc wg show to show the median round-trip time to each WireGuard peer.

Local machine upstreams first in Caddyfile​

Change: 45cf87a

The generated Caddyfile now lists upstreams from the local machine first for each service.

On its own this doesn't change routing behaviour (Caddy's default random load balancing policy ignores order). But if you pair it with the first policy in a custom Caddy config, you can always prefer the same-host replica and only fall back to remote machines when the local one is unhealthy.

services:
  app:
    ...
    x-caddy: |
      example.com {
          reverse_proxy {{upstreams 8000}} {
              import common_proxy
              lb_policy first
          }
          log
      }

This saves a cross-machine WireGuard hop for every request that hits Caddy on the machine which already has a replica of the target service. This is especially useful if you have a multi-region setup.

Nightly builds​

PR: #308. Thanks to @tonyo for the contribution ❤️

Every push to main now produces a set of nightly binaries tagged as the nightly release on GitHub.

They're great for testing upcoming unreleased changes and reporting regressions early. They might be unstable, so please don't run them in production.

Install the nightly uc CLI locally:

curl -fsS https://get.uncloud.run/install.sh | VERSION=nightly sh

Initialise a cluster or add a machine with a nightly daemon:

uc machine init --version nightly user@host
uc machine add --version nightly user@host

Improvements​

  • uc machine init/add now embed the install script into the uc binary and send it to the remote machine over the existing SSH connection instead of curl | bash (fe829ef).
  • New uc ctx show command prints the name of the currently active cluster context, great for shell prompts and scripts (#317).
  • SSH connections now use -o StrictHostKeyChecking=accept-new, which silently accepts host keys on first connection but still protects against key changes later (#303).
  • The STORE column in uc images is hidden when all machines use the containerd image store, which is the default for new clusters (c38d916)
  • Image push errors now include the underlying error from the unregistry proxy, which makes it much easier to tell apart a broken image push from a broken SSH tunnel (d340659)
  • ucind now accepts a UNCLOUD_CONFIG environment variable to override the config file path for development clusters (#315).
  • New ucind cluster ls command lists the local development clusters managed by ucind with their machines (#316).

Bug fixes​

  • Fixed containerd socket auto-detection for unregistry after a machine reboot (47199c3).
  • Fixed Caddy config being regenerated on every service change because container records were serialised non-deterministically (#111).
  • Fixed SSH control socket path on WSL2 when the runtime directory doesn't exist (#319).
  • Fixed a stale SSH ControlMaster connection sometimes causing uc machine init/add to hang (fdbffbf).

Upgrade to 0.19.0​

Uncloud CLI locally​

To upgrade the Uncloud CLI (uc) locally:

# Homebrew (macOS, Linux)
brew upgrade uncloud

# Install script (macOS, Linux)
curl -fsS https://get.uncloud.run/install.sh | sh

Machine daemon​

To upgrade the Uncloud daemon on your machines, run the following commands on each machine:

ARCH=$(uname -m | sed 's/x86_64/amd64/;s/aarch64/arm64/')
curl -fsSL -o uncloudd.tar.gz https://github.com/psviderski/uncloud/releases/download/v0.19.0/uncloudd_linux_${ARCH}.tar.gz
tar -xf uncloudd.tar.gz
sudo install uncloudd /usr/local/bin/uncloudd
rm uncloudd uncloudd.tar.gz
sudo systemctl restart uncloud