Name: dockerd
Author: mgksu

Overview

Running containerized microservices and developer environments directly on an Android handset turns mobile hardware into an ultra-low-power, portable Linux server. However, Android’s stock kernel configuration lacks critical virtualization primitives—such as namespace separation, cgroup memory limits, and OverlayFS mount capabilities—and stock root distributions lack Docker daemon binaries.

Developed by mgksu, dockerd packages a complete, native Docker engine (dockerd) and command-line client (docker) formatted specifically for rooted ARM64 Android environments. Accompanied by a dedicated service control wrapper, the module manages container lifecycle states across device reboots without requiring a full Linux chroot.

Hardware & Kernel Requirements

Container virtualization directly interfaces with Linux kernel primitives. Before installing this module, ensure your environment meets the following criteria:

CPU Architecture: Strictly arm64 (64-bit ARM). 32-bit (armv7) and x86_64 devices are unsupported.
Docker-Patched Kernel: Android stock OEM kernels have essential container flags disabled. You must run a custom kernel compiled with:
- Namespaces (CONFIG_NAMESPACES, CONFIG_IPC_NS, CONFIG_PID_NS, CONFIG_NET_NS, CONFIG_UTS_NS)
- Control Groups (CONFIG_CGROUPS, CONFIG_MEMCG, CONFIG_CGROUP_SCHED)
- File Systems (CONFIG_OVERLAY_FS)
- Networking (CONFIG_NETFILTER_XT_MATCH_ADDRTYPE, CONFIG_NETFILTER_XT_MATCH_CONNTRACK, CONFIG_IP_NF_FILTER, CONFIG_IP_NF_TARGET_MASQUERADE)
- Tip: You can evaluate your current kernel compatibility by running the upstream check-config.sh diagnostic script inside Termux.

Environment Setup & PATH Configuration

The module deploys its binaries into /data/adb/docker/bin and manages its socket runtime in /data/adb/docker/run/. To make docker and management commands accessible from any interactive shell (such as Termux):

Open your shell profile (e.g., ~/.bashrc or ~/.zshrc) in Termux or root shell.

Add the following export declarations:

export PATH=/data/adb/docker/bin:$PATH
export DOCKER_HOST="unix:///data/adb/docker/run/docker.sock"

Source the updated profile:
```
source ~/.bashrc
```

Service Control (`dockerd.service`)

The module provides an init utility, dockerd.service, to supervise the background daemon without manually managing PID files:

Check Daemon Status & Logs:
```
su -c dockerd.service logs
```
Restart Docker:
```
su -c dockerd.service restart
```
Stop Daemon:
```
su -c dockerd.service stop
```
Start Daemon:
```
su -c dockerd.service start
```

Running Containers

Once the service is active, standard Docker CLI commands operate as expected:

# Verify daemon connectivity
su -c docker info

# Pull and run a lightweight Alpine container
su -c docker run -it --rm alpine sh

# Host a local Nginx web server
su -c docker run -d -p 8080:80 --name webserver nginx:alpine

Troubleshooting

Error: “Cannot connect to the Docker daemon”: Check whether the daemon is active using su -c dockerd.service logs. If the daemon aborted during startup, verify that DOCKER_HOST is pointing to unix:///data/adb/docker/run/docker.sock.
OverlayFS or iptables Errors: Inspect dmesg output. If dockerd logs show overlayfs: filesystem not supported or missing network tables, your kernel is missing required kernel config flags and must be recompiled.

dockerd