### CLI: krunvm start

Source: https://github.com/containers/krunvm/blob/main/docs/krunvm-start.1.txt

Starts an existing microVM created by krunvm-create, allowing for optional configuration overrides and command execution.

```APIDOC
## CLI: krunvm start

### Description
Starts an existing microVM created by krunvm-create(1) and attaches stdin/stdout to its virtio-console.

### Method
CLI Command

### Endpoint
krunvm start [OPTIONS] microVM [COMMAND] [-- ARGS]

### Parameters
#### Path Parameters
- **microVM** (string) - Required - The name or identifier of the microVM to start.

#### Options
- **--cpus** (NUM) - Optional - Override the number of vCPUs configured for this microVM.
- **--mem** (NUM) - Optional - Override amount of RAM, in MiB, configured for this microVM.
- **--env** (KEY=VALUE) - Optional - Set environment variable to be passed to the microVM.

### Request Example
krunvm start my-vm --cpus 2 --mem 1024 --env DEBUG=1 -- /bin/sh
```

--------------------------------

### Install krunvm on Fedora

Source: https://github.com/containers/krunvm/blob/main/README.md

Install krunvm on Fedora by enabling necessary COPR repositories and then installing the package using DNF.

```bash
dnf copr enable -y slp/libkrunfw
dnf copr enable -y slp/libkrun
dnf copr enable -y slp/krunvm
dnf install -y krunvm
```

--------------------------------

### Install krunvm on macOS

Source: https://context7.com/containers/krunvm/llms.txt

Use Homebrew to tap the krun repository and install the krunvm binary.

```bash
# Tap the krun repository and install krunvm
brew tap slp/krun
brew install krunvm
```

--------------------------------

### Start a microVM with custom configurations

Source: https://context7.com/containers/krunvm/llms.txt

Override default CPU and memory settings or pass environment variables to the containerized process.

```bash
krunvm start fedora-dev /bin/bash --cpus 4
```

```bash
krunvm start fedora-dev /bin/bash --mem 4096
```

```bash
krunvm start python-dev /usr/local/bin/python -- /workspace/app.py \
    --env PYTHONPATH=/workspace \
    --env DATABASE_URL=localhost:5432
```

```bash
krunvm start node-app /bin/sh
```

--------------------------------

### Start MicroVMs

Source: https://context7.com/containers/krunvm/llms.txt

Launch a microVM and optionally execute commands or set environment variables.

```bash
# Start a microVM and run its default entrypoint
krunvm start my-ubuntu

# Start a microVM and run a specific shell
krunvm start my-ubuntu /bin/bash

# Start a microVM and run a command with arguments
krunvm start my-ubuntu /bin/cat -- /etc/os-release

# Start with environment variables
krunvm start python-dev /usr/local/bin/python --env DEBUG=true --env PORT=8000
```

--------------------------------

### Install krunvm on macOS

Source: https://github.com/containers/krunvm/blob/main/README.md

Use Homebrew to install krunvm on macOS. Ensure the slp/krun tap is added first.

```bash
brew tap slp/krun
brew install krunvm
```

--------------------------------

### GET /krunvm/list

Source: https://github.com/containers/krunvm/blob/main/docs/krunvm-list.1.txt

Lists all microVMs created by krunvm-create that have not been removed by krunvm-delete.

```APIDOC
## GET /krunvm/list

### Description
Lists the existing microVMs created by krunvm-create that have not been removed by krunvm-delete.

### Method
GET

### Endpoint
/krunvm/list
```

--------------------------------

### Build krunvm from Sources

Source: https://github.com/containers/krunvm/blob/main/README.md

Build krunvm from its source code using Cargo. Ensure Rust toolchain, libkrun, buildah, and asciidoctor are installed as dependencies.

```bash
cargo build --release
```

--------------------------------

### Build krunvm from Source

Source: https://context7.com/containers/krunvm/llms.txt

Clone the repository and compile the project using Cargo.

```bash
# Clone the repository and build
git clone https://github.com/containers/krunvm
cd krunvm
cargo build --release
```

--------------------------------

### Manage krunvm Global Configuration

Source: https://context7.com/containers/krunvm/llms.txt

View or update default settings for CPU, RAM, and DNS for new microVMs.

```bash
# View current global configuration
krunvm config

# Output:
# Global configuration:
# Default number of CPUs for newly created VMs: 2
# Default amount of RAM (MiB) for newly created VMs: 1024
# Default DNS server for newly created VMs: 1.1.1.1

# Set default number of vCPUs for new microVMs (max 8)
krunvm config --cpus 4

# Set default RAM in MiB for new microVMs (max 16384)
krunvm config --mem 2048

# Set default DNS server for new microVMs
krunvm config --dns 8.8.8.8

# Configure all defaults at once
krunvm config --cpus 4 --mem 4096 --dns 1.1.1.1
```

--------------------------------

### Create MicroVMs

Source: https://context7.com/containers/krunvm/llms.txt

Create and configure microVMs from OCI images with options for resources, volumes, and networking.

```bash
# Create a basic microVM from an Alpine image with default settings
krunvm create docker.io/library/alpine:latest

# Create a microVM with a custom name, 2 vCPUs, and 1024 MiB RAM
krunvm create docker.io/library/ubuntu:22.04 --name my-ubuntu --cpus 2 --mem 1024

# Create a microVM with volume mappings (host_path:guest_path)
krunvm create docker.io/library/fedora:38 \
    --name fedora-dev \
    -v /home/user/projects:/projects \
    -v /home/user/data:/data

# Create a microVM with port mappings (host_port:guest_port)
krunvm create docker.io/library/nginx:latest \
    --name webserver \
    --port 8080:80 \
    --port 8443:443

# Create a microVM with a custom working directory
krunvm create docker.io/library/node:18 \
    --name node-app \
    --workdir /app \
    -v /home/user/myapp:/app

# Create a fully configured microVM with all options
krunvm create docker.io/library/python:3.11 \
    --name python-dev \
    --cpus 4 \
    --mem 2048 \
    --dns 8.8.8.8 \
    --workdir /workspace \
    -v /home/user/code:/workspace \
    --port 5000:5000

# On macOS ARM64: Create an x86_64 microVM using Rosetta (limited to 1 CPU)
krunvm create docker.io/library/debian:latest --name x86-debian --x86
```

--------------------------------

### krunvm create

Source: https://github.com/containers/krunvm/blob/main/docs/krunvm-create.1.txt

Creates a new microVM from an OCI image with configurable hardware and environment settings.

```APIDOC
## krunvm create

### Description
Creates a new microVM from the OCI image specified by IMAGE.

### Method
CLI Command

### Endpoint
krunvm create [OPTIONS] IMAGE

### Parameters
#### Path Parameters
- **IMAGE** (string) - Required - The OCI image to use for the microVM.

#### Options
- **--cpus** (NUM) - Optional - The number of vCPUs for the microVM.
- **--mem** (NUM) - Optional - The amount of RAM in MiB available to the microVM.
- **--name** (NAME) - Optional - The name to be assigned to the microVM.
- **-p, --port** (HOST_PORT:GUEST_PORT) - Optional - Exposes a guest port through a host port. Can be specified multiple times.
- **-v, --volume** (HOST_PATH:GUEST_PATH) - Optional - Maps a host path to a guest path. Can be specified multiple times.
- **-w, --workdir** (GUEST_PATH) - Optional - Sets the working directory for the first binary executed in the microVM.
```

--------------------------------

### List MicroVMs

Source: https://context7.com/containers/krunvm/llms.txt

Display status and configuration details for all created microVMs.

```bash
# List all existing microVMs
krunvm list

# Example output:
# my-ubuntu
#  CPUs: 2
#  RAM (MiB): 1024
#  DNS server: 1.1.1.1
#  Buildah container: ubuntu-working-container
#  Workdir: /root
#  Mapped volumes: {}
#  Mapped ports: {}
#
# webserver
#  CPUs: 2
#  RAM (MiB): 1024
#  DNS server: 1.1.1.1
#  Buildah container: nginx-working-container
#  Workdir:
#  Mapped volumes: {}
#  Mapped ports: {"8080": "80", "8443": "443"}
```

--------------------------------

### Configure Linux user namespace

Source: https://context7.com/containers/krunvm/llms.txt

Use buildah unshare to handle user namespaces when running as a non-root user on Linux.

```bash
buildah unshare krunvm create docker.io/library/alpine:latest --name my-alpine
```

```bash
buildah unshare
# Now inside the unshare session:
krunvm create docker.io/library/alpine:latest --name my-alpine
krunvm start my-alpine /bin/sh
krunvm delete my-alpine
exit
```

--------------------------------

### POST /changevm

Source: https://github.com/containers/krunvm/blob/main/docs/krunvm-changevm.1.txt

Modifies the configuration of an existing microVM or displays current settings if no options are provided.

```APIDOC
## POST /changevm

### Description
Changes the configuration of an existing microVM. When run without options, it displays the current configuration.

### Method
POST

### Endpoint
/changevm

### Parameters
#### Query Parameters
- **microVM** (string) - Required - The identifier of the microVM to modify.
- **--remove-ports** (flag) - Optional - Removes all port mappings.
- **--remote-volumes** (flag) - Optional - Removes all volume mappings.
- **--cpus** (integer) - Optional - Changes the number of vCPUs.
- **--mem** (integer) - Optional - Changes the amount of RAM in MiB.
- **--name** (string) - Optional - Assigns a new name to the microVM.
- **-p, --port** (string) - Optional - Exposes a port (format: HOST_PORT:GUEST_PORT). Can be specified multiple times.
- **-v, --volume** (string) - Optional - Maps a host path to a guest path (format: HOST_PATH:GUEST_PATH). Can be specified multiple times.
- **-w, --workdir** (string) - Optional - Configures the working directory for the first binary executed.
```

--------------------------------

### krunvm delete

Source: https://github.com/containers/krunvm/blob/main/docs/krunvm-delete.1.txt

Deletes an existing microVM configuration and requests buildah to unmount and remove the OCI image backing it.

```APIDOC
## DELETE /containers/krunvm/{microVM}

### Description
Deletes an existing microVM configuration and requests buildah to unmount and remove the OCI image that was backing it.

### Method
DELETE

### Endpoint
/containers/krunvm/{microVM}

### Parameters
#### Path Parameters
- **microVM** (string) - Required - The name or ID of the microVM to delete.

### Response
#### Success Response (200)
- **message** (string) - Confirmation message indicating the microVM was deleted.

#### Error Response (404)
- **error** (string) - Message indicating the microVM was not found.
```

--------------------------------

### Configure macOS APFS volume

Source: https://context7.com/containers/krunvm/llms.txt

Set up a case-sensitive APFS volume required for storing container images on macOS.

```bash
diskutil apfs addVolume disk3 "Case-sensitive APFS" krunvm
```

```bash
krunvm create docker.io/library/alpine:latest
```

--------------------------------

### Modify microVM configuration

Source: https://context7.com/containers/krunvm/llms.txt

Update CPU, memory, name, volumes, ports, or working directory for an existing microVM.

```bash
krunvm changevm my-ubuntu
```

```bash
krunvm changevm my-ubuntu --cpus 4
```

```bash
krunvm changevm my-ubuntu --mem 4096
```

```bash
krunvm changevm my-ubuntu --new-name ubuntu-server
```

```bash
krunvm changevm python-dev --workdir /app
```

```bash
krunvm changevm python-dev \
    -v /home/user/newproject:/project \
    -v /home/user/config:/config
```

```bash
krunvm changevm python-dev --remove-volumes
```

```bash
krunvm changevm webserver \
    --port 80:80 \
    --port 443:443 \
    --port 8080:8080
```

```bash
krunvm changevm webserver --remove-ports
```

```bash
krunvm changevm my-vm \
    --new-name production-vm \
    --cpus 8 \
    --mem 8192 \
    --workdir /app \
    -v /data:/data \
    --port 3000:3000
```

--------------------------------

### Delete a microVM

Source: https://context7.com/containers/krunvm/llms.txt

Permanently remove a microVM configuration and its backing OCI image.

```bash
krunvm delete my-ubuntu
```

```bash
krunvm create docker.io/library/alpine:latest --name temp-vm
krunvm start temp-vm /bin/sh
# ... do some work ...
krunvm delete temp-vm
```

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