runs-on/action

RunsOn Action for magic caching, and more. This action is required if you are using the magic caching feature of RunsOn (extras=s3-cache job label).

Usage

jobs:
  build:
    runs-on: runs-on=${{ github.run_id }}/runner=2cpu-linux-x64/extras=s3-cache
    steps:
      - uses: runs-on/action@v2
      - other steps

Options

show_env

Show all environment variables available to actions (used for debugging purposes).

jobs:
  build:
    runs-on: runs-on=${{ github.run_id }}/runner=2cpu-linux-x64/extras=s3-cache
    steps:
      - uses: runs-on/action@v2
        with:
          show_env: true

Possible values:

• true - Show all environment variables
• false - Don't show environment variables (default)

show_costs

Displays how much it cost to run that workflow job. Uses https://ec2-pricing.runs-on.com to get accurate data, for both on-demand and spot pricing across all regions and availability zones.

Beta: also compares with similar machine on GitHub.

Example output in the post-step:

| metric                 | value           |
| ---------------------- | --------------- |
| Instance Type          | m7i-flex.large  |
| Instance Lifecycle     | on-demand       |
| Region                 | us-east-1       |
| Duration               | 2.06 minutes    |
| Cost                   | $0.0040         |
| GitHub equivalent cost | $0.0240         |
| Savings                | $0.0200 (82.8%) |

Possible values:

• inline - Display costs in the action log output (default)
• summary - Display costs in the action log output and in the GitHub job summary
• Any other value - Disables the feature

metrics

Note: this is currently only available with a development release of RunsOn. This will be fully functional with v2.8.4+

Send additional metrics using CloudWatch agent.

Supported metrics:

Metric Type	Available Metrics
cpu	usage_user, usage_system
network	bytes_recv, bytes_sent
memory	used_percent
disk	used_percent, inodes_used
io	io_time, reads, writes

jobs:
  build:
    runs-on: runs-on=${{ github.run_id }}/runner=2cpu-linux-x64/extras=s3-cache
    steps:
      - uses: runs-on/action@v2
        with:
          metrics: cpu,network,memory,disk,io

Possible values:

• cpu - CPU usage metrics (usage_user, usage_system)
• network - Network metrics (bytes_recv, bytes_sent)
• memory - Memory metrics (used_percent)
• disk - Disk metrics (used_percent, inodes_used)
• io - I/O metrics (io_time, reads, writes)
• Comma-separated combinations (e.g., cpu,network,memory,disk,io)
• Empty string - No additional metrics (default)

The action will display live metrics with charts in the post-execution summary.

📈 Metrics (since 2025-06-30T14:18:56Z):


📊 CPU User:
   100.0 ┤
    87.5 ┤                                        ╭─╮╭───────────╮
    75.0 ┤                                       ╭╯ ╰╯           │
    62.5 ┤                                      ╭╯               ╰╮
    50.0 ┤                                      │                 │
    37.5 ┤                                      │                 ╰╮
    25.0 ┤                                     ╭╯                  │
    12.5 ┤                    ╭─────────╮╭─────╯                   ╰╮
     0.0 ┼────────────────────╯         ╰╯                          ╰
                               CPU User (Percent)
  Stats: min:0.0 avg:29.0 max:93.4 Percent


📊 Memory Used:
   100.0 ┤
    87.5 ┤
    75.0 ┤
    62.5 ┤
    50.0 ┤
    37.5 ┤
    25.0 ┤                                             ╭────────╮
    12.5 ┤                            ╭──╮      ╭──────╯        ╰───╮
     0.0 ┼────────────────────────────╯  ╰──────╯                   ╰
                             Memory Used (Percent)
  Stats: min:0.5 avg:7.4 max:20.9 Percent

Example full output:

📈 Metrics (since 2025-06-30T14:18:56Z):


📊 CPU User:
   100.0 ┤
    87.5 ┤                                        ╭─╮╭───────────╮
    75.0 ┤                                       ╭╯ ╰╯           │
    62.5 ┤                                      ╭╯               ╰╮
    50.0 ┤                                      │                 │
    37.5 ┤                                      │                 ╰╮
    25.0 ┤                                     ╭╯                  │
    12.5 ┤                    ╭─────────╮╭─────╯                   ╰╮
     0.0 ┼────────────────────╯         ╰╯                          ╰
                               CPU User (Percent)
  Stats: min:0.0 avg:29.0 max:93.4 Percent



📊 CPU System:
   100.0 ┤
    87.5 ┤
    75.0 ┤
    62.5 ┤
    50.0 ┤
    37.5 ┤
    25.0 ┤                                     ╭──╮
    12.5 ┤                                    ╭╯  ╰──────────────╮
     0.0 ┼────────────────────────────────────╯                  ╰───
                              CPU System (Percent)
  Stats: min:0.2 avg:5.0 max:33.7 Percent



📊 Memory Used:
   100.0 ┤
    87.5 ┤
    75.0 ┤
    62.5 ┤
    50.0 ┤
    37.5 ┤
    25.0 ┤                                             ╭────────╮
    12.5 ┤                            ╭──╮      ╭──────╯        ╰───╮
     0.0 ┼────────────────────────────╯  ╰──────╯                   ╰
                             Memory Used (Percent)
  Stats: min:0.5 avg:7.4 max:20.9 Percent



📊 Disk Used:
   100.0 ┤
    87.5 ┤
    75.0 ┤            ╭──────────────────────────────────────────────
    62.5 ┤         ╭──╯
    50.0 ┤   ╭─────╯
    37.5 ┼───╯
    25.0 ┤
    12.5 ┤
     0.0 ┤
                              Disk Used (Percent)
  Stats: min:35.6 avg:68.7 max:75.8 Percent



📊 Disk Inodes Used:
   481238 ┤           ╭───────────────────────────────────────────────
   450852 ┤          ╭╯
   420466 ┤          │
   390080 ┤         ╭╯
   359694 ┤         │
   329307 ┤        ╭╯
   298921 ┤       ╭╯
   268535 ┤   ╭───╯
   238149 ┼───╯
                            Disk Inodes Used (Inodes)
  Stats: min:238149.0 avg:440393.1 max:481238.0 Inodes



📊 Disk IO Time:
   10000 ┤             ╭─╮
    8750 ┤   ╭╮       ╭╯ ╰╮
    7500 ┤   ││      ╭╯   │
    6251 ┤   ││      │    │
    5001 ┤  ╭╯╰╮ ╭╮ ╭╯    │
    3751 ┤  │  │ ││ │     ╰╮
    2502 ┤  │  │╭╯╰─╯      │
    1252 ┤ ╭╯  ╰╯          ╰╮                ╭──╮
       2 ┼─╯                ╰────────────────╯  ╰────────────────────
                               Disk IO Time (ms)
  Stats: min:1.0 avg:1581.3 max:10000.0 ms



📊 Disk Reads:
   1472 ┤   ╭╮
   1288 ┤   ││
   1104 ┤   ││
    920 ┤  ╭╯│
    736 ┤  │ ╰╮
    552 ┤  │  │
    368 ┤  │  │         ╭─╮
    184 ┤ ╭╯  ╰╮       ╭╯ ╰─╮
      0 ┼─╯    ╰───────╯    ╰───────────────────────────────────────
                              Disk Reads (Ops/s)
  Stats: min:0.0 avg:81.8 max:1519.0 Ops/s



📊 Disk Writes:
   18816 ┤            ╭─╮
   16465 ┤         ╭──╯ ╰╮
   14113 ┤        ╭╯     ╰╮
   11762 ┤   ╭╮  ╭╯       │
    9411 ┤   ││  │        │
    7059 ┤  ╭╯╰╮╭╯        ╰╮
    4708 ┤  │  ││          │
    2356 ┤ ╭╯  ╰╯          │                ╭───╮
       5 ┼─╯               ╰────────────────╯   ╰────────────────────
                              Disk Writes (Ops/s)
  Stats: min:4.0 avg:3373.4 max:19192.0 Ops/s



📊 Network Received:
   934237025 ┤ ╭╮
   817458485 ┤ ││     ╭─╮
   700679945 ┤ ││    ╭╯ │
   583901406 ┤╭╯│    │  │
   467122866 ┤│ ╰╮   │  │
   350344327 ┤│  │  ╭╯  ╰╮
   233565787 ┼╯  │  │    │
   116787247 ┤   │  │    │
        8708 ┤   ╰──╯    ╰───────────────────────────────────────────────
                                Network Received (Bytes)
  Stats: min:8707.0 avg:91377905.1 max:950344235.0 Bytes



📊 Network Sent:
   1866827 ┼╮
   1634232 ┤│
   1401638 ┤╰╮
   1169043 ┤ │
    936449 ┤ ╰╮
    703854 ┤  │    ╭──╮
    471259 ┤  ╰╮  ╭╯  │
    238665 ┤   │  │   ╰╮                        ╭╮
      6070 ┤   ╰──╯    ╰────────────────────────╯╰─────────────────────
                                Network Sent (Bytes)
  Stats: min:6068.0 avg:159559.6 max:1866827.0 Bytes

sccache

Only available for Linux runners.

Configures sccache so that you can cache the compilation of C/C++ code, Rust, as well as NVIDIA's CUDA.

The only parameter it can take for now is s3, which will auto-configure the S3 cache backend for sccache, using the RunsOn S3 cache bucket that comes for free (with crazy speed and unlimited storage) with your RunsOn installation.

Example:

jobs:
  build:
    runs-on: runs-on=${{ github.run_id }}/runner=2cpu-linux-x64/extras=s3-cache
    steps:
      - uses: runs-on/action@v2
        with:
          sccache: s3
      - uses: mozilla-actions/sccache-action@v0.0.9
      - run: # your slow rust compilation

Possible values:

• s3 - Use RunsOn S3 cache bucket for sccache backend
• Empty string - Disable sccache configuration (default)

What this does under the hood is the equivalent of:

echo "SCCACHE_GHA_ENABLED=false" >> $GITHUB_ENV
echo "SCCACHE_BUCKET=${{ env.RUNS_ON_S3_BUCKET_CACHE}}" >> $GITHUB_ENV
echo "SCCACHE_REGION=${{ env.RUNS_ON_AWS_REGION}}" >> $GITHUB_ENV
echo "SCCACHE_S3_KEY_PREFIX=cache/sccache" >> $GITHUB_ENV
echo "RUSTC_WRAPPER=sccache" >> $GITHUB_ENV

Development

Make your source code changes in a commit, then push the updated binaries and JS files in a separate commit:

make release

Future work

This action will probably host a few other features such as:

• enabling/disabling SSM agent ?