Mosquitto : Adds Eclipse Mosquitto broker

[vTusharr]

This pr adds the Eclipse Mosquitto (Version 2.1.2) MQTT broker to the Unikraft catalog-core. Mosquitto is a lightweight message broker that implements the MQTT protocol versions 5.0, 3.1.1 and 3.1.

features supported

• MQTT publish/subscribe over TCP (IPv4 only)
• In-memory persistence to /data in the initrd,(can also configure 9pfs)

related pr

• Library port: relies on unikraft/lib-mosquitto#1

testing

Builds cleanly for qemu and fc on x86_64 and arm64 via
./.scripts/build/<plat>.<arch>. Verified booting under qemu-system-x86_64
with bridged networking, and bidirectional messaging from the host with
mosquitto_pub/mosquitto_sub; ./test.sh automates that round trip.

[vTusharr]

Maybe i should add dfifferent config options in mosquitto.conf in readme ?

[Copilot]

Pull request overview

Adds a new Mosquitto MQTT broker application to the Unikraft catalog-core, including build/run scaffolding and platform configs for QEMU, Firecracker, and Xen, plus rootfs configuration.

Changes:

• Adds a new mosquitto/ app directory with Kconfig (Config.uk), build wrapper (Makefile), setup script, and documentation.
• Introduces platform run configurations (Firecracker JSON, Xen cfg) and defconfig presets (QEMU x86_64/arm64).
• Updates the top-level setup.sh to fetch the required lib-mosquitto dependency.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
setup.sh	Clones lib-mosquitto into the standard repos layout.
mosquitto/xen.x86_64.cfg	Adds Xen PV config to boot Mosquitto with initrd-based rootfs.
mosquitto/xen.arm64.cfg	Adds Xen arm64 config (currently uses type = "pvh").
mosquitto/setup.sh	Creates workdir/ and symlinks required repos for the Mosquitto app.
mosquitto/scripts/defconfig/qemu.x86_64	Adds x86_64 QEMU defconfig (currently missing explicit Mosquitto enablement).
mosquitto/scripts/defconfig/qemu.arm64	Adds arm64 QEMU defconfig with virtio/net/9p and Mosquitto symbols enabled.
mosquitto/rootfs/etc/mosquitto/mosquitto.conf	Provides broker config (listener, anonymous access, persistence settings).
mosquitto/README.md	Documents setup/build/run/test steps for QEMU/Firecracker/Xen.
mosquitto/Makefile.uk	Added (empty, consistent with some other catalog apps).
mosquitto/Makefile	Build wrapper invoking Unikraft with required libs and build dir.
mosquitto/fc.x86_64.json	Firecracker x86_64 boot config.
mosquitto/fc.arm64.json	Firecracker arm64 boot config.
mosquitto/Config.uk	Kconfig selecting Mosquitto + networking + filesystem dependencies.
mosquitto/.gitignore	Ignores generated build artifacts and runtime files.

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[Copilot]

Pull request overview

Copilot reviewed 25 out of 26 changed files in this pull request and generated no new comments.

Suppressed comments (10)

mosquitto/test.sh:16

• mosquitto_sub | grep -qx treats the expected message as a regular expression; use fixed-string matching so the test can’t fail if the message ever contains regex metacharacters.

mosquitto_sub -h "$HOST" -p "$PORT" -t "$TOPIC" -C 1 -W 5 | grep -qx "$MSG"

mosquitto/rootfs/etc/mosquitto/mosquitto.conf:12

• There’s trailing whitespace and an extra leading space in the persistence comment, which makes the shipped config look sloppy and can trip whitespace-sensitive tooling.

# Set to "none" to silence the broker. 
log_dest stdout
# /data/ lives in the in-memory root filesystem, so the database survives a
#  restart 
persistence true

mosquitto/.scripts/run/qemu.x86_64:15

• This script continues even if network setup or initrd packing fails; add set -e so failures stop early. If you do that, the best-effort cleanup block should be explicitly ignored (|| true) so missing interfaces don’t abort the run.

#!/bin/sh

if test ! -f "workdir/build/mosquitto_qemu-x86_64"; then
    echo "No kernel file workdir/build/mosquitto_qemu-x86_64." 1>&2
    echo "Did you run ./.scripts/build/qemu.x86_64 ?" 1>&2

mosquitto/.scripts/run/qemu.arm64:15

• This script continues even if network setup or initrd packing fails; add set -e so failures stop early. If you do that, the best-effort cleanup block should be explicitly ignored (|| true) so missing interfaces don’t abort the run.

#!/bin/sh

if test ! -f "workdir/build/mosquitto_qemu-arm64"; then
    echo "No kernel file workdir/build/mosquitto_qemu-arm64." 1>&2
    echo "Did you run ./.scripts/build/qemu.arm64 ?" 1>&2

mosquitto/.scripts/run/fc.x86_64:15

• This script continues even if network setup or initrd packing fails; add set -e so failures stop early. If you do that, the best-effort cleanup block should be explicitly ignored (|| true) so missing interfaces don’t abort the run.

#!/bin/sh

if test ! -f "workdir/build/mosquitto_fc-x86_64"; then
    echo "No kernel file workdir/build/mosquitto_fc-x86_64." 1>&2
    echo "Did you run ./.scripts/build/fc.x86_64 ?" 1>&2

mosquitto/.scripts/run/fc.arm64:15

• This script continues even if network setup or initrd packing fails; add set -e so failures stop early. If you do that, the best-effort cleanup block should be explicitly ignored (|| true) so missing interfaces don’t abort the run.

#!/bin/sh

if test ! -f "workdir/build/mosquitto_fc-arm64"; then
    echo "No kernel file workdir/build/mosquitto_fc-arm64." 1>&2
    echo "Did you run ./.scripts/build/fc.arm64 ?" 1>&2

mosquitto/.scripts/build/qemu.x86_64:4

• Defaulting to -w suppresses all compiler warnings, which can hide real build issues. Also consider set -e so a failing make step stops the script immediately.

#!/bin/sh
export UK_CFLAGS="${UK_CFLAGS:--std=gnu17 -w}"

make distclean

mosquitto/.scripts/build/qemu.arm64:4

• Defaulting to -w suppresses all compiler warnings, which can hide real build issues. Also consider set -e so a failing make step stops the script immediately.

#!/bin/sh
export UK_CFLAGS="${UK_CFLAGS:--std=gnu17 -w}"

make distclean

mosquitto/.scripts/build/fc.x86_64:4

• Defaulting to -w suppresses all compiler warnings, which can hide real build issues. Also consider set -e so a failing make step stops the script immediately.

#!/bin/sh
export UK_CFLAGS="${UK_CFLAGS:--std=gnu17 -w}"

make distclean

mosquitto/.scripts/build/fc.arm64:4

• Defaulting to -w suppresses all compiler warnings, which can hide real build issues. Also consider set -e so a failing make step stops the script immediately.

#!/bin/sh
export UK_CFLAGS="${UK_CFLAGS:--std=gnu17 -w}"

make distclean

[AndreiRV1]

Looks good overall, but the build script currently fails to complete because several required dependencies are missing.

Please ensure LIBVFSCORE and LIBSYSCALL_SHIM are explicitly selected in the configuration so the full dependency chain is satisfied and the project builds without errors.

[vTusharr]

Looks good overall, but the build script currently fails to complete because several required dependencies are missing.

Please ensure LIBVFSCORE and LIBSYSCALL_SHIM are explicitly selected in the configuration so the full dependency chain is satisfied and the project builds without errors.

Vfscore should be set to imply as per this
, I am using the newer posix-vfs stack so i set that to n & syscall-shim is auto selected by musl . Adding it wont have any effect so for documentation purposes we can add it + Can you please share the logs of the build errors you got upon using the script.

[vTusharr]

Also @AndreiRV1 can you also review this at your covenience ?
Thanks

[Copilot]

Pull request overview

Copilot reviewed 25 out of 26 changed files in this pull request and generated 3 comments.

Suppressed comments (4)

mosquitto/README.md:14

• This quick-setup snippet assumes /etc/qemu already exists, but the listed requirements do not guarantee that; on a clean host tee fails and the subsequent bridge-backed QEMU launch cannot work. Add the directory creation step used by the top-level README (README.md:74) before writing bridge.conf.

echo "allow all" | sudo tee /etc/qemu/bridge.conf

mosquitto/README.md:67

• xl create is not sufficient with these configs: both Xen files require a virbr0 bridge with the guest gateway at 172.44.0.1, but this section never creates/configures that bridge, and it also omits the mkcpio command needed to produce initrd.cpio. On a clean Xen host the command therefore fails or boots an unreachable broker. Add the network and initrd setup steps before the xl command, as in redis/README.md:302-319.

Xen has no scripts. Build it by passing [.scripts/defconfig/](.scripts/defconfig/)
style options to `make menuconfig`, pack the initrd yourself, then boot it with
`sudo xl create -c xen.x86_64.cfg` on a system with Xen installed.

mosquitto/README.md:28

• These quick-start commands invoke the host mosquitto_sub/mosquitto_pub clients, but the referenced shared requirements and CI base dependency list do not install mosquitto-clients. On a clean setup following this README, the commands fail with command not found; document or install that app-specific prerequisite.

mosquitto_sub -h 172.44.0.2 -t test/unikraft

mosquitto/test.sh:16

• grep -qx interprets MSG as a basic regular expression, so the . in Unikraft! matches any character and a corrupted response such as UnikraftX would still make this round-trip test pass. Use fixed-string matching (grep -Fqx) so the assertion checks the exact payload.

mosquitto_sub -h "$HOST" -p "$PORT" -t "$TOPIC" -C 1 -W 5 | grep -qx "$MSG"