Act on many hosts at once

The desktop app can run a snippet, push a file or pull a file on many hosts in one go, and list what every host runs. It connects from your computer to each host in turn, the same way a normal connection does (jump hosts, proxies, the same prompts). Nothing runs on a Sternway server.

Choose the hosts

Each of these starts with Which hosts:

• Pick hosts ticks hosts one by one.
• By tag rule chooses tags and whether a host needs any of them or all of them. The line under it says which hosts the rule picks now. The rule is read again each time the action runs, so a host tagged since is included.

Run a snippet and collect the results

1. In Snippets, open a snippet’s menu and choose Run on hosts….
2. Choose the hosts, and under How it runs pick:
   • Open terminals: a session per host, in one tab, with the script typed into each.
   • Collect results: the script runs on each host over a channel of its own, four hosts at a time, with nothing typed into a terminal.
3. With Collect results, a table shows each host’s status, exit status, how long it ran and its last four lines. Show output has everything it printed (up to 64 KB); Run again on failed repeats it where it failed or was cancelled.

Save these targets as default keeps the hosts, or the tag rule, with the snippet for next time.

Caution

Collect results has no terminal to answer questions in. A command that asks for something (sudo’s password, a yes/no prompt) waits, and the run on that host stops after two minutes.

Push a file to many hosts

Hosts › More › Push a file… (or Push a file… on a selection): one file from this computer into a folder on each host, four hosts at a time, over SFTP. Choose Replace or Skip for hosts where the file is already there. Push again retries the hosts that failed.

Pull a file from many hosts

Hosts › More › Pull a file…: the same file from each host into one zip on this computer, three hosts at a time. Each host’s copy goes in a folder named after the host (web/os-release, db/os-release). A file larger than Largest file to fetch (50 MB unless you choose 1 MB to 1 GB) is left out and marked Too large. Pull again fetches from the hosts that failed and writes the zip anew.

List what your hosts run

Hosts › More › Inventory (on the phone: Hosts › ⋯ › Inventory) lists each host with its operating system, version and architecture, as Sternway’s check found them when it last connected, and when this device last connected to it. A host never connected to from this device has empty columns. Export CSV (phone: Share CSV) writes host,address,os,version,arch,lastSeen.

Running on hosts, pushing and pulling are on the desktop only for now; the phone has the inventory.

From scripts

sternway-cli run <snippet> --hosts a,b does the same as Collect results from a terminal or a script: see Use the command line.