├── LICENSE
├── README.md
└── fly-to-podman.sh


/LICENSE:
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 1 | MIT License
 2 | 
 3 | Copyright (c) 2025 Eduard Tolosa
 4 | 
 5 | Permission is hereby granted, free of charge, to any person obtaining a copy
 6 | of this software and associated documentation files (the "Software"), to deal
 7 | in the Software without restriction, including without limitation the rights
 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 9 | copies of the Software, and to permit persons to whom the Software is
10 | furnished to do so, subject to the following conditions:
11 | 
12 | The above copyright notice and this permission notice shall be included in all
13 | copies or substantial portions of the Software.
14 | 
15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 | SOFTWARE.
22 | 


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/README.md:
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 1 | # fly-to-podman
 2 | Migrate from Docker to Podman.
 3 | 
 4 | fly-to-podman is a small bash script that helps you migrate from Docker to Podman. It will migrate your Docker containers, images, and volumes to Podman, as well as keep your container data and configurations (mounts, ports, etc.) intact.
 5 | 
 6 | Full blog post: [From Docker to Podman: full migration to rootless](https://www.edu4rdshl.dev/posts/from-docker-to-podman-full-migration-to-rootless/)
 7 | 
 8 | # What it does
 9 | 
10 | - Migrate Docker images to Podman (including tags)
11 | - Migrate Docker volumes to Podman (including all data)
12 | - Migrate Docker networks to Podman (including names, IPs, gateways, IP ranges, etc.)
13 | - Migrate Docker containers to Podman (including names, IDs, and statuses such as restart policy, etc.)
14 | - Keep container data and configurations (mounts, exposed ports, etc.)
15 | 
16 | # Requirements
17 | 
18 | - Docker
19 | - Podman
20 | - bash
21 | - jq
22 | - rsync
23 | 
24 | # Usage
25 | 
26 | ```bash
27 | fly-to-podman.sh {images|volumes|containers|full}
28 |         images: Migrate Docker images to Podman
29 |         volumes: Migrate Docker volumes to Podman
30 |         containers: Migrate Docker containers to Podman
31 |         networks: Migrate Docker networks to Podman
32 |         full: Migrate Docker images, volumes, and containers to Podman
33 | ```
34 | 
35 | # Issues and contributions
36 | 
37 | If you find any issues or have any suggestions, please open an issue or a pull request.
38 | 


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/fly-to-podman.sh:
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  1 | #!/bin/bash
  2 | # This script is used to migrate from Docker to Podman
  3 | 
  4 | # Migrate images
  5 | migrate_images() {
  6 |     echo "Migrating Docker images to Podman..."
  7 |     # Get a list of all Docker images (name:tag)
  8 |     docker images --format "{{.Repository}}:{{.Tag}}" | while read -r image; do
  9 |         # Skip <none>:<none> images
 10 |         if [[ "$image" == "<none>:<none>" ]]; then
 11 |             continue
 12 |         fi
 13 | 
 14 |         # Replace slashes in repository names with underscores for filenames
 15 |         filename=$(echo "$image" | tr '/' '_').tar
 16 | 
 17 |         echo "Exporting $image..."
 18 |         docker save -o "$filename" "$image" &&
 19 |             podman load -i "$filename" &&
 20 |             echo "Image $image migrated to Podman" || echo "Failed to migrate image $image"
 21 | 
 22 |         # Remove temporary file
 23 |         rm -f "$filename"
 24 |     done
 25 | }
 26 | 
 27 | # Migrate volumes
 28 | migrate_volumes() {
 29 |     echo "Migrating Docker volumes to Podman..."
 30 |     # Get the path to the Podman volumes directory (and guess at the Docker volumes directory)
 31 |     PODMAN_VOLUMES_PATH=$(podman info --format json | jq -r '.store.volumePath')
 32 |     DOCKER_VOLUMES_PATH=$(docker system info -fjson | jq -r '.DockerRootDir')/volumes
 33 | 
 34 |     RSYNC_OPTS=""
 35 |     if [[ "$UID" -ne 0 ]]; then
 36 |         # If not running as root, make sure to chown the files to the current user
 37 |         RSYNC_OPTS+=" --chown=$(id -u):$(id -g)"
 38 |     fi
 39 | 
 40 |     for volume in $(docker volume ls --format json | jq -r '.Name'); do
 41 |         echo "Migrating volume: $volume"
 42 |         podman volume create "$volume" &&
 43 |             sudo rsync -a "$RSYNC_OPTS" "$DOCKER_VOLUMES_PATH/$volume/_data/" "$PODMAN_VOLUMES_PATH/$volume/_data"
 44 |     done
 45 | }
 46 | 
 47 | # Migrate networks
 48 | migrate_networks() {
 49 |     echo "Migrating Docker networks to Podman..."
 50 | 
 51 |     # Get all Docker networks
 52 |     for network in $(docker network ls --format '{{json . }}' | jq -r '.Name'); do
 53 |         echo "Processing network: $network"
 54 | 
 55 |         # Skip default Docker networks
 56 |         if [[ "$network" == "host" || "$network" == "none" ]]; then
 57 |             echo "Skipping network: $network (Podman does not need it)"
 58 |             continue
 59 |         fi
 60 | 
 61 |         # Extract network details
 62 |         NETWORK_JSON=$(docker network inspect "$network" | jq '.[0]')
 63 |         DRIVER=$(echo "$NETWORK_JSON" | jq -r '.Driver')
 64 |         SUBNET=$(echo "$NETWORK_JSON" | jq -r '.IPAM.Config[0].Subnet // empty')
 65 |         GATEWAY=$(echo "$NETWORK_JSON" | jq -r '.IPAM.Config[0].Gateway // empty')
 66 |         IP_RANGE=$(echo "$NETWORK_JSON" | jq -r '.IPAM.Config[0].IPRange // empty')
 67 | 
 68 |         # Check if the network already exists in Podman
 69 |         if podman network exists "$network"; then
 70 |             echo "Network $network already exists in Podman. Skipping creation."
 71 |             continue
 72 |         fi
 73 | 
 74 |         # Build the Podman network create command
 75 |         PODMAN_NET_CMD="podman network create"
 76 | 
 77 |         # Add driver (Podman supports `bridge`, `ipvlan` and `macvlan`)
 78 |         case "$DRIVER" in
 79 |         "bridge")
 80 |             PODMAN_NET_CMD+=" --driver bridge"
 81 |             ;;
 82 |         "macvlan")
 83 |             PODMAN_NET_CMD+=" --driver macvlan"
 84 |             ;;
 85 |         "ipvlan")
 86 |             PODMAN_NET_CMD+=" --driver ipvlan"
 87 |             ;;
 88 |         *)
 89 |             echo "Warning: Unsupported network driver '$DRIVER' in Podman. Using default bridge."
 90 |             PODMAN_NET_CMD+=" --driver bridge"
 91 |             ;;
 92 |         esac
 93 | 
 94 |         # Add subnet configuration if available
 95 |         if [[ -n "$SUBNET" ]]; then
 96 |             PODMAN_NET_CMD+=" --subnet $SUBNET"
 97 |         fi
 98 | 
 99 |         # Add gateway if available
100 |         if [[ -n "$GATEWAY" ]]; then
101 |             PODMAN_NET_CMD+=" --gateway $GATEWAY"
102 |         fi
103 | 
104 |         # Add IP range if available
105 |         if [[ -n "$IP_RANGE" ]]; then
106 |             PODMAN_NET_CMD+=" --ip-range $IP_RANGE"
107 |         fi
108 | 
109 |         # Finalize the command with network name
110 |         PODMAN_NET_CMD+=" $network"
111 | 
112 |         # Create the Podman network
113 |         echo "Creating Podman network: $network"
114 |         eval "$PODMAN_NET_CMD" && echo "Network $network migrated successfully." ||
115 |             echo "Failed to migrate network: $network"
116 | 
117 |     done
118 | }
119 | 
120 | # Migrate containers
121 | migrate_containters() {
122 |     echo "Migrating Docker containers to Podman..."
123 |     for container in $(docker container ls -a --format json | jq -r '.Names'); do
124 |         # Convert container name to lowercase
125 |         container_lc=$(echo "$container" | tr '[:upper:]' '[:lower:]')
126 |         # Tag for the image to be created from the container
127 |         MIGRATION_CONTAINER_TAG="podman.local/${container_lc}-to-podman:latest"
128 |         # Get Running status from Docker
129 |         WAS_RUNNING=$(docker container inspect -f '{{.State.Running}}' "$container")
130 |         # Get RestartPolicy from Docker
131 |         RESTART_POLICY=$(docker inspect -f '{{.HostConfig.RestartPolicy.Name}}' "$container")
132 | 
133 |         # Pass the restart policy to Podman
134 |         case "$RESTART_POLICY" in
135 |         "no") PODMAN_RESTART="" ;;
136 |         "always") PODMAN_RESTART="--restart=always" ;;
137 |         "unless-stopped") PODMAN_RESTART="--restart=unless-stopped" ;;
138 |         "on-failure") PODMAN_RESTART="--restart=on-failure" ;;
139 |         *) PODMAN_RESTART="" ;;
140 |         esac
141 | 
142 |         echo "Processing container: $container"
143 | 
144 |         # Commit container to an image. It lets us start a new container with the _same_ state and add additional options
145 |         docker commit "$container" "$MIGRATION_CONTAINER_TAG" &&
146 |             docker save -o "$container_lc".tar "$MIGRATION_CONTAINER_TAG" &&
147 |             podman load -i "$container_lc".tar || {
148 |             echo "Failed to migrate image for $container"
149 |             continue
150 |         }
151 | 
152 |         # Extract volume/bind mount information from Docker container
153 |         MOUNT_OPTS=""
154 |         while read -r mount; do
155 |             MOUNT_TYPE=$(echo "$mount" | jq -r '.Type')
156 |             SOURCE=$(echo "$mount" | jq -r '.Source')
157 |             DESTINATION=$(echo "$mount" | jq -r '.Destination')
158 |             READ_WRITE=$(echo "$mount" | jq -r '.RW')
159 | 
160 |             # Pass the RW/RO setting to Podman
161 |             if [[ "$READ_WRITE" == "true" ]]; then
162 |                 MODE="rw"
163 |             else
164 |                 MODE="ro"
165 |             fi
166 | 
167 |             if [[ "$MOUNT_TYPE" == "volume" ]]; then
168 |                 # Use :U to ensure right permissions inside the container.
169 |                 # It tells Podman to use the correct host UID and GID based on the UID and GID within the <<container|pod>>
170 |                 MODE+=",U"
171 |                 # Attach existing named volume
172 |                 VOLUME_NAME=$(echo "$mount" | jq -r '.Name')
173 |                 MOUNT_OPTS+=" -v $VOLUME_NAME:$DESTINATION:$MODE"
174 |             elif [[ "$MOUNT_TYPE" == "bind" ]]; then
175 |                 # Use :Z if you're using SELinux to ensure right permissions inside the container
176 |                 # MODE+=",Z"
177 |                 # Ensure the source path exists before mounting
178 |                 [[ -e "$SOURCE" ]] && MOUNT_OPTS+=" -v $SOURCE:$DESTINATION:$MODE"
179 |             fi
180 |         done < <(docker inspect "$container" | jq -c '.[0].Mounts[]')
181 | 
182 |         # Extract port mappings
183 |         PORT_OPTS=""
184 |         while read -r port_mapping; do
185 |             HOST_IP=$(echo "$port_mapping" | jq -r '.HostIp')
186 |             HOST_PORT=$(echo "$port_mapping" | jq -r '.HostPort')
187 |             CONTAINER_PORT=$(echo "$port_mapping" | jq -r '.ContainerPort')
188 |             PROTOCOL=$(echo "$port_mapping" | jq -r '.Protocol')
189 | 
190 |             # Construct `-p` option (exclude 0.0.0.0 for readability)
191 |             if [[ "$HOST_IP" == "0.0.0.0" || -z "$HOST_IP" ]]; then
192 |                 PORT_OPTS+=" -p $HOST_PORT:$CONTAINER_PORT/$PROTOCOL"
193 |             else
194 |                 PORT_OPTS+=" -p $HOST_IP:$HOST_PORT:$CONTAINER_PORT/$PROTOCOL"
195 |             fi
196 |         done < <(docker inspect "$container" | jq -c '.[] | .NetworkSettings.Ports | to_entries[] | {ContainerPort: .key, Protocol: (if .key | contains("udp") then "udp" else "tcp" end), HostMappings: .value} | select(.HostMappings != null) | .HostMappings[] | {HostIp, HostPort, ContainerPort, Protocol}')
197 | 
198 |         # Extract network information
199 |         NETWORK_OPTS=""
200 |         while read -r network; do
201 |             NETWORK_NAME=$(echo "$network" | jq -r 'keys[0]')
202 |             NETWORK_IP=$(echo "$network" | jq -r ".$NETWORK_NAME.IPAddress")
203 | 
204 |             if [[ -n "$NETWORK_NAME" ]]; then
205 |                 NETWORK_OPTS+=" --network=$NETWORK_NAME"
206 |             fi
207 | 
208 |             if [[ -n "$NETWORK_IP" ]]; then
209 |                 NETWORK_OPTS+=" --ip=$NETWORK_IP"
210 |             fi
211 |         done < <(docker inspect "$container" | jq -c '.[0].NetworkSettings.Networks')
212 | 
213 |         # Run the container with the same name and mounts, including RW/RO options
214 |         podman run -d --name "$container" $PODMAN_RESTART "$MOUNT_OPTS" "$PORT_OPTS" "$NETWORK_OPTS" "$MIGRATION_CONTAINER_TAG" &&
215 |             echo "Container $container migrated successfully" ||
216 |             echo "Failed to migrate container: $container"
217 | 
218 |         # Stop the container if this was not running, this allow us to keep the container ready to `podman container start $container`
219 |         if [[ "$WAS_RUNNING" == "false" ]]; then
220 |             podman stop "$container"
221 |         fi
222 |     done
223 | }
224 | 
225 | # Process arguments
226 | case "$1" in
227 | images)
228 |     migrate_images
229 |     ;;
230 | volumes)
231 |     migrate_volumes
232 |     ;;
233 | containers)
234 |     migrate_containters
235 |     ;;
236 | networks)
237 |     migrate_networks
238 |     ;;
239 | full)
240 |     migrate_images
241 |     migrate_volumes
242 |     migrate_networks
243 |     migrate_containters
244 |     ;;
245 | *)
246 |     echo "Usage: $0 {images|volumes|containers|full}"
247 |     echo -e "\timages: Migrate Docker images to Podman"
248 |     echo -e "\tvolumes: Migrate Docker volumes to Podman"
249 |     echo -e "\tcontainers: Migrate Docker containers to Podman"
250 |     echo -e "\tnetworks: Migrate Docker networks to Podman"
251 |     echo -e "\tfull: Migrate Docker images, volumes, and containers to Podman"
252 |     exit 1
253 |     ;;
254 | esac
255 | 


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