norrietaylor · Jun 26, 2026 · Jun 26, 2026 · Jun 26, 2026
@@ -1,21 +1,28 @@
-let { BuildSpec, Local, OutputData, .. } = import "minimal.ncl" in
+let { subsetOf, BuildSpec, Local, OutputData, .. } = import "minimal.ncl" in
 let base = import "../base/build.ncl" in
 let e2fsprogs = import "../e2fsprogs/build.ncl" in
 let git = import "../git/build.ncl" in
+let iproute2 = import "../iproute2/build.ncl" in
+let util-linux = import "../util-linux/build.ncl" in
 {
   name = "microvm-rootfs",
 
   # A read-only ext4 guest userland for a libkrun microVM. build.sh snapshots
-  # the runtime closure (base + git), prunes build-only bulk, and packs an ext4
-  # image loaded as a virtio-blk block device (/dev/vda). The guest minimald
-  # ships as the initramfs pid-1, mounts this image, and chroots into it — there
-  # is no standalone init in the image itself. e2fsprogs is build-only (mke2fs to
-  # pack the image) and its files are removed before packing, so the image ships
-  # only the runtime closure. git is in the closure because the in-guest minimald
-  # session bring-up inits a minimal context that shells out to git.
+  # the runtime closure (base + git + networking tools), prunes build-only bulk,
+  # and packs an ext4 image loaded as a virtio-blk block device (/dev/vda). The
+  # guest minimald ships as the initramfs pid-1, mounts this image, and chroots
+  # into it — there is no standalone init in the image itself. e2fsprogs is
+  # build-only (mke2fs to pack the image) and its files are removed before
+  # packing, so the image ships only the runtime closure. git is in the closure
+  # because the in-guest minimald session bring-up inits a minimal context that
+  # shells out to git. iproute2 (ip) and util-linux's nsenter give the guest
+  # network/namespace plumbing — only the nsenter output is pulled from
+  # util-linux (subsetOf), not its whole ~18 MB toolset.
   runtime_deps = [
     base,
     git,
+    iproute2,
+    subsetOf util-linux ["nsenter"],
   ],
   build_deps = [
     { file = "build.sh" } | Local,

@@ -24,10 +24,19 @@ done
 # e2fsprogs is a build-only dependency: it provides mke2fs to pack the image
 # below (invoked from the build sandbox PATH, not from $STAGE), but the guest
 # never needs it at runtime. Drop its staged files so the runtime image carries
-# only the runtime closure. The symlink guard skips a usr-merged /usr/sbin.
-if [ -d "$STAGE/usr/sbin" ] && [ ! -L "$STAGE/usr/sbin" ]; then
-  rm -rf "$STAGE/usr/sbin"
-fi
+# only the runtime closure. Remove e2fsprogs's sbin tools by name rather than
+# nuking usr/sbin wholesale: iproute2 installs `ip` (and ss/tc/bridge) into
+# /usr/sbin (SBINDIR=/usr/sbin) and that must survive into the guest. The list
+# is the full e2fsprogs sbin set — nothing else in the runtime closure ships
+# these names (util-linux is pulled as `subsetOf ["nsenter"]`, so its blkid/
+# findfs/fsck/uuidd never reach the image and the e2fsprogs copies must go).
+# rm -f tolerates names this e2fsprogs config happens not to build.
+for tool in badblocks blkid debugfs dumpe2fs e2freefrag e2fsck e2image e2label \
+            e2mmpstatus e2scrub e2scrub_all e2undo e4crypt filefrag findfs fsck \
+            fsck.ext2 fsck.ext3 fsck.ext4 logsave mke2fs mkfs.ext2 mkfs.ext3 \
+            mkfs.ext4 mklost+found resize2fs tune2fs uuidd; do
+  rm -f "$STAGE/usr/sbin/$tool"
+done
 rm -f "$STAGE"/usr/bin/chattr "$STAGE"/usr/bin/lsattr "$STAGE"/usr/bin/uuidgen \
       "$STAGE"/usr/bin/compile_et "$STAGE"/usr/bin/mk_cmds
 # Note: `libss.so*` (not `libss*.so*`) — the latter also matches openssl's

@@ -12,8 +12,12 @@ cd "opencode-${MINIMAL_ARG_VERSION}"
 bun_version="$(bun --version)"
 sed -i "s/\"packageManager\": \"bun@[^\"]*\"/\"packageManager\": \"bun@${bun_version}\"/" package.json
 
-# Install monorepo dependencies (requires network access).
-bun install --frozen-lockfile --ignore-scripts
+# Install monorepo dependencies (requires network access). NOT --frozen-lockfile:
+# our shipped bun resolves upstream's committed lockfile differently and rejects
+# it, and this install already network-fetches deps (so it isn't hermetic anyway),
+# so let bun float the lockfile. Proper fix = a vendored, bun-version-matched
+# bun.lock (tracked in a pkgs issue).
+bun install --ignore-scripts
 
 # The build script consults git for a channel name when these are unset;
 # set them explicitly so it doesn't shell out to git in the sandbox.

@@ -30,6 +30,11 @@ let version = "2.42.1" in
     bins = { glob = "usr/bin/*" } | OutputBin,
     sbins = { glob = "usr/sbin/*" } | OutputBin,
 
+    # Granular single-tool output so a consumer can `subsetOf util-linux
+    # ["nsenter"]` (just the binary + glibc) instead of pulling the whole
+    # ~18 MB toolset. nsenter links only libc, so no extra outputs are needed.
+    nsenter = { glob = "usr/bin/nsenter" } | OutputBin,
+
     libblkid = { glob = "usr/lib/libblkid*.so*" } | OutputLib,
     libfdisk = { glob = "usr/lib/libfdisk*.so*" } | OutputLib,
     libmount = { glob = "usr/lib/libmount*.so*" } | OutputLib,