Colima and Docker on macOS

Docker is a very popular tool to package applications and their dependencies into containers. Colima is an alternative to Docker Desktop for macOS and Linux.

Time to time, I use docker containers for my personal projects. Since my use case is not daily work, I keep forgetting the commands. So, I wanted to put some of the relevant commands into a note.

Installation and Setup

On macOS, the easiest way is to use Homebrew.

brew install colima docker docker-compose docker-Buildx

Create Docker CLI plugins folder:

mkdir -p ~/.docker/cli-plugins

symlink docker-compose:

ln -sfn $(brew --prefix)/opt/docker-compose/bin/docker-compose ~/.docker/cli-plugins/docker-compose

symlink docker-buildx:

ln -sfn $(brew --prefix)/opt/docker-buildx/bin/docker-buildx ~/.docker/cli-plugins/docker-buildx

Starting Colima

Colima runs containers in a virtual machine with 2 CPUs, 2GiB memory and 60GiB storage (which can be changed). An image will be downloaded on the first run.

colima start

output:

INFO[0000] starting colima
INFO[0000] runtime: docker
INFO[0000] preparing network ...                         context=vm
INFO[0000] starting ...                                  context=vm
INFO[0021] provisioning ...                              context=docker
INFO[0021] starting ...                                  context=docker
INFO[0027] done

Custom VM

The following creates a VM w/ 4 CPUs, 4GB RAM, and 100 GiB storage space,

colima start --cpu 4 --memory 4 --disk 100

Emulate x86_64

The following creates a Colima profile named amd64 that emulates x86_64 architecture,

colima start --profile amd64 -a x86_64

Native virtualization on macOS

In order to use Apple's native virtualization framework (requires macOS 13+):

colima start --arch aarch64 --vm-type=vz

• arch: architecture (aarch64, x86_64)
• vm-type: virtual machine type (qemu, vz)
  • vz: Apple's virtualization framework.
  • vz-rosetta: enable Rosetta for amd64 emulation

List

colima ls

output:

PROFILE    STATUS     ARCH       CPUS    MEMORY    DISK     RUNTIME    ADDRESS
default    Running    aarch64    4       4GiB      32GiB    docker

Setting Colima context

docker context ls

output:

NAME             DESCRIPTION                               DOCKER ENDPOINT                                  ERROR
colima           colima                                    unix:///Users/acm/.colima/default/docker.sock
colima-amd64 *   colima [profile=amd64]                    unix:///Users/acm/.colima/amd64/docker.sock
default          Current DOCKER_HOST based configuration   unix:///var/run/docker.sock

To set the docker context,

docker context use [NAME]

Containers

List containers

docker ps -a

output:

CONTAINER ID   IMAGE         COMMAND    CREATED          STATUS                      PORTS     NAMES
b552ba797fe3   hello-world   "/hello"   20 seconds ago   Exited (0) 19 seconds ago             naughty_kapitsa

Remove container

docker rm [CONTAINER]

Copy files/folders

docker cp container_id:/tmp/foo/tmpfile.txt .

docker cp ./tmpfile.txt container_id:/tmp/foo/

container_id can be found via docker ps -a command.

Images

Running hello-world image

If the hello-world image is not found, it will be downloaded.

docker run hello-world

output:

Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
70f5ac315c5a: Pull complete
Digest: sha256:dcba6daec718f547568c562956fa47e1b03673dd010fe6ee58ca806767031d1c
Status: Downloaded newer image for hello-world:latest

Hello from Docker!

Interactive w/ terminal and auto-remove:

Allocates a pseudo-TTY and keeps STDIN open, and automatically removes the container when it exits.

docker run --rm -it [IMAGE]

List images

docker images

output:

REPOSITORY           TAG         IMAGE ID       CREATED        SIZE
hello-world          latest      b038788ddb22   4 months ago   9.14kB
arm64v8/rockylinux   8           1632c4ad6456   3 months ago   220MB
arm64v8/rockylinux   9-minimal   d9b75e890280   3 months ago   129MB

Remove images

docker rmi [IMAGE]

Build image

For building custom images, we use a Dockerfile, such as the following;

# syntax=docker/dockerfile:1

FROM arm64v8/rockylinux:8 AS builder

WORKDIR /bundle

COPY src .
COPY CMakeLists.txt .

RUN dnf install dnf-plugins-core epel-release -y
RUN dnf config-manager --set-enabled powertools
RUN dnf install ninja-build -y

RUN dnf install git cmake -y

# RUN dnf group install "Development Tools" -y
RUN dnf install binutils bison flex gcc gcc-c++ gdb glibc-devel libtool make rpm-build -y

RUN cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -S . -B ./build/Release
RUN cmake --build ./build/Release

Building an image called docker-test:

docker build -t docker-test .