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Allow Sandbox container limits overrides

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Jarek Rozanski 2026-09-28 12:01:20 +02:00
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@ -86,7 +86,7 @@ Bumping a pinned LSP version means editing the corresponding `ARG`/`FROM` tag in
Because these are real host paths shared by every container regardless of workdir, logging into OpenCode once carries over to every project you use the sandbox in.
- Both run targets join a shared, auto-created Podman network (`opencode-sandbox-net`) under a `--network-alias` derived from the current directory's name, so a container started from another dev-container setup on the same network can reach this one by that name (and vice versa).
- Both run targets also cap the container to `--memory=3072m --memory-swap=3072m --cpus=4`. Without this, a heavy JVM build tool (Gradle's daemon plus its separate Kotlin-compiler daemon are the worst offenders — both auto-size their heap off "available" memory with no idea they're sharing a fixed-size VM) can consume the entire `podman machine`'s RAM. That starves the VM's own guest kernel, which stalls the processes Podman itself needs to stay responsive — so the *whole machine* hangs, not just the container. The cap forces a contained OOM kill instead. Sized to leave headroom below the VM's own allocation for the VM/podman/gvproxy itself — adjust both together if you resize the machine (`podman machine set --memory <MB> --cpus <N> podman-machine-default`, machine must be stopped first). The `Containerfile` also sets a default `GRADLE_OPTS=-Xmx1024m` so the Gradle daemon itself doesn't try to claim the whole container ceiling; a project whose Kotlin-compiler daemon also needs bounding should set `kotlin.daemon.jvmargs` in its own `gradle.properties`.
- Both run targets also cap the container to `--memory=3072m --memory-swap=3072m --cpus=4`. Without this, a heavy JVM build tool (Gradle's daemon plus its separate Kotlin-compiler daemon are the worst offenders — both auto-size their heap off "available" memory with no idea they're sharing a fixed-size VM) can consume the entire `podman machine`'s RAM. That starves the VM's own guest kernel, which stalls the processes Podman itself needs to stay responsive — so the *whole machine* hangs, not just the container. The cap forces a contained OOM kill instead. Sized to leave headroom below the VM's own allocation for the VM/podman/gvproxy itself — adjust both together if you resize the machine (`podman machine set --memory <MB> --cpus <N> podman-machine-default`, machine must be stopped first). The `Containerfile` also sets a default `GRADLE_OPTS=-Xmx1024m` so the Gradle daemon itself doesn't try to claim the whole container ceiling; a project whose Kotlin-compiler daemon also needs bounding should set `kotlin.daemon.jvmargs` in its own `gradle.properties`. These defaults can be overridden per-invocation by exporting `OPENCODE_SANDBOX_MEMORY`, `OPENCODE_SANDBOX_MEMORY_SWAP`, and/or `OPENCODE_SANDBOX_CPUS` before running `make opencode`/`make shell` (e.g. `OPENCODE_SANDBOX_MEMORY=4096m OPENCODE_SANDBOX_CPUS=6 make shell`).
## macOS-specific notes