Migration to CRDs

Custom Resources Generator

Up until release v0.12 MetalLB was configured via MetalLB’s ConfigMap. Deprecating the ConfigMap impacts on the users’ current configurations. To mitigate this, the MetalLB resource generator is an offline tool to convert the ConfigMap into the new CRDs.

Procedure

In order to use the tool, the following container must be run with the ConfigMap config.yaml mapped into the /var/input folder. On success it will generate a resources.yaml file containing the new MetalLB CRD based config. This example assumes MetalLB was installed in the metallb-system namespace and the ConfigMap was named config:

kubectl get configmap -n metallb-system -o yaml config > config.yaml
docker run -d -v $(pwd):/var/input quay.io/metallb/configmaptocrs

Example

For this MetalLB ConfigMap named config.yaml:

apiVersion: v1
kind: ConfigMap
metadata:
  namespace: metallb-system
  name: config
data:
  config: |
    peers:
    - my-asn: 64512
      peer-asn: 64512
      peer-address: 10.96.0.100
    address-pools:
    - name: my-ip-space
      protocol: bgp
      addresses:
      - 198.51.100.0/24
      bgp-advertisements:
      - aggregation-length: 32
        localpref: 100
        communities:
        - 64512:1234

The generator will generate a resources.yaml file that looks like:

# This was autogenerated by MetalLB's custom resource generator.
apiVersion: metallb.io/v1beta2
kind: BGPPeer
metadata:
  creationTimestamp: null
  name: peer1
  namespace: metallb-system
spec:
  holdTime: 1m30s
  keepaliveTime: 0s
  myASN: 64512
  passwordSecret: {}
  peerASN: 64512
  peerAddress: 10.96.0.100
status: {}
---
apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  creationTimestamp: null
  name: my-ip-space
  namespace: metallb-system
spec:
  addresses:
  - 198.51.100.0/24
status: {}
---
apiVersion: metallb.io/v1beta1
kind: BGPAdvertisement
metadata:
  creationTimestamp: null
  name: bgpadvertisement1
  namespace: metallb-system
spec:
  aggregationLength: 32
  communities:
  - 64512:1234
  ipAddressPools:
  - my-ip-space
  localPref: 100
status: {}
---

Running directly against a cluster

Configmaptocrs tool can also run directly against a cluster, and print the CRs corresponding to the ConfigMap deployed on the cluster to the standard output.

kubectl run configmaptocrs -n metallb-system --restart=Never -it --rm --image overriden --overrides '
{
  "spec": {
    "containers": [
      {
        "name": "configmaptocrs",
        "image": "quay.io/metallb/configmaptocrs",
        "command": [
          "/configmaptocrs",
          "-source",
          "config",
          "-only-data",
          "-stdout"
        ],
        "volumeMounts": [
          {
            "name": "config",
            "mountPath": "/var/input"
          }
        ]
      }
    ],
    "volumes": [
      {
        "name": "config",
        "configMap": {
          "name": "config"
        }
      }
    ]
  }
}'

In this case, for the same ConfigMap as above, the output should look like:

2022/09/11 19:58:19 MetalLB generator starting. commit: fb96318 branch: main goversion: gc / go1.18.3 / amd64
2022/09/11 19:58:19 Reading configmap
2022/09/11 19:58:19 Decoding configmap
2022/09/11 19:58:19 Creating custom resources
2022/09/11 19:58:19 Checking the resources are parsed correctly
2022/09/11 19:58:19 Creating the output YAML
# This was autogenerated by MetalLB's custom resource generator.
apiVersion: metallb.io/v1beta2
kind: BGPPeer
metadata:
  creationTimestamp: null
  name: peer1
  namespace: metallb-system
spec:
  holdTime: 1m30s
  keepaliveTime: 0s
  myASN: 64512
  passwordSecret: {}
  peerASN: 64512
  peerAddress: 10.96.0.100
status: {}
---
apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  creationTimestamp: null
  name: my-ip-space
  namespace: metallb-system
spec:
  addresses:
  - 198.51.100.0/24
status: {}
---
apiVersion: metallb.io/v1beta1
kind: BGPAdvertisement
metadata:
  creationTimestamp: null
  name: bgpadvertisement1
  namespace: metallb-system
spec:
  aggregationLength: 32
  communities:
  - 64512:1234
  ipAddressPools:
  - my-ip-space
  localPref: 100
status: {}
---
pod "configmaptocrs" deleted

Options of configmaptocrs:

-source string

name of the input file to convert (default "./config.yaml")

-only-data bool

set this to true if the input file is only the configMap data

-stdout bool

set this to true to output the crds to stdout