Red Hat build of MicroShift

Perform a dry run

You can use oc-mirror to perform a dry run so that you can review the list of images to be mirrored. By using a dry run, you can catch any errors with your image set configuration early or use the generated list of images with other tools to conduct mirroring.

Prerequisites

You have access to the internet to obtain the necessary container images.
You installed the OpenShift CLI (oc).
You installed the oc-mirror CLI plugin.
You created the image set configuration file.

Procedure

Run the oc mirror command with the --dry-run flag to perform a dry run:

$ oc-mirror --config <ImageSetConfig.yaml> docker://localhost:5000 --workspace file://<outm2m> --dry-run --v2

where:

ImageSetConfig.yaml

Specifies the name of the image set configuration file that you created.

docker://localhost:5000

Specifies the mirror registry. Nothing is mirrored to this registry when you use the --dry-run flag.

--workspace file://<outm2m>

Insert the address of the workspace path.

--dry-run

The dry run flag generates the dry run artifacts and not an actual image set file.

--v2

Specifies oc mirror v2.

Example output

2025/08/25 15:50:44  [INFO]   : 👋 Hello, welcome to oc-mirror
2025/08/25 15:50:44  [INFO]   : ⚙  setting up the environment for you...
2025/08/25 15:50:44  [INFO]   : 🔀 workflow mode: mirrorToMirror
2025/08/25 15:50:44  [INFO]   : 🕵  going to discover the necessary images...
2025/08/25 15:50:44  [INFO]   : 🔍 collecting release images...
2025/08/25 15:50:44  [INFO]   : 🔍 collecting operator images...
 ✓   (1m30s) Collecting catalog registry.redhat.io/redhat/redhat-operator-index:v4.20
2025/08/25 15:52:14  [INFO]   : 🔍 collecting additional images...
2025/08/25 15:52:14  [INFO]   : 📄 list of all images for mirroring in : wspace/working-dir/dry-run/mapping.txt
2025/08/25 15:52:14  [INFO]   : mirror time     : 1m30.399585837s
2025/08/25 15:52:14  [INFO]   : 👋 Goodbye, thank you for using oc-mirror

Review the mapping.txt file that was generated by running the following command:

$ cat wspace/working-dir/dry-run/mapping.txt

Example output

docker://registry.redhat.io/amq8/amq-broker-rhel9@sha256:47fd4ce2533496828aba37bd1f9715e2164d5c90bd0fc6b25e7e0786d723bf01=docker://mirror.com/amq8/amq-broker-rhel9:sha256-47fd4ce2533496828aba37bd1f9715e2164d5c90bd0fc6b25e7e0786d723bf01
docker://registry.redhat.io/amq8/amq-broker-init-rhel9@sha256:9cc48eecf1442ae04b8543fa5d4381a13bc2831390850828834d387006d1342b=docker://mirror.com/amq7/amq-broker-init-rhel9:sha256-9cc48eecf1442ae04b8543fa5d4381a13bc2831390850828834d387006d1342b
docker://registry.redhat.io/amq8/amq-broker-rhel9@sha256:bb6fbd68475a7852b4d99eea6c4ab313f9267da7963162f0d75375d7063409e7=docker://mirror.com/amq8/amq-broker-rhel9:sha256-bb6fbd68475a7852b4d99eea6c4ab313f9267da7963162f0d75375d7063409e7
docker://registry.redhat.io/amq8/amq-broker-rhel9@sha256:d42d713da0ce6806fdc6492b6342586783e6865a82a8647d3c4288439b1751ee=docker://mirror.com/amq8/amq-broker-rhel9:sha256-d42d713da0ce6806fdc6492b6342586783e6865a82a8647d3c4288439b1751ee
docker://registry.redhat.io/amq8/amq-broker-init-rhel9@sha256:ffffa9875f0379e9373f89f05eb06e5a193273bb04bc3aa5f85b044357b79098=docker://mirror.com/amq8/amq-broker-init-rhel9:sha256-ffffa9875f0379e9373f89f05eb06e5a193273bb04bc3aa5f85b044357b79098