Upgrade Guide

This upgrade guide is intended for Cilium running on Kubernetes. If you have questions, feel free to ping us on the Slack channel.

Warning

Read the full upgrade guide to understand all the necessary steps before performing them.

Do not upgrade to 1.13.0 before reading the section 1.13.3+ Upgrade Notes and completing the required steps. Skipping this step may lead to an non-functional upgrade.

Running pre-flight check (Required)

When rolling out an upgrade with Kubernetes, Kubernetes will first terminate the pod followed by pulling the new image version and then finally spin up the new image. In order to reduce the downtime of the agent and to prevent ErrImagePull errors during upgrade, the pre-flight check pre-pulls the new image version. If you are running in Kubernetes Without kube-proxy mode you must also pass on the Kubernetes API Server IP and / or the Kubernetes API Server Port when generating the cilium-preflight.yaml file.

helm template cilium/cilium --version 1.13.3 \
  --namespace=kube-system \
  --set preflight.enabled=true \
  --set agent=false \
  --set operator.enabled=false \
  > cilium-preflight.yaml
kubectl create -f cilium-preflight.yaml

helm install cilium-preflight cilium/cilium --version 1.13.3 \
  --namespace=kube-system \
  --set preflight.enabled=true \
  --set agent=false \
  --set operator.enabled=false

helm template cilium/cilium --version 1.13.3 \
  --namespace=kube-system \
  --set preflight.enabled=true \
  --set agent=false \
  --set operator.enabled=false \
  --set k8sServiceHost=API_SERVER_IP \
  --set k8sServicePort=API_SERVER_PORT \
  > cilium-preflight.yaml
kubectl create -f cilium-preflight.yaml

helm install cilium-preflight cilium/cilium --version 1.13.3 \
  --namespace=kube-system \
  --set preflight.enabled=true \
  --set agent=false \
  --set operator.enabled=false \
  --set k8sServiceHost=API_SERVER_IP \
  --set k8sServicePort=API_SERVER_PORT

After applying the cilium-preflight.yaml, ensure that the number of READY pods is the same number of Cilium pods running.

$ kubectl get daemonset -n kube-system | sed -n '1p;/cilium/p'
NAME                      DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR   AGE
cilium                    2         2         2       2            2           <none>          1h20m
cilium-pre-flight-check   2         2         2       2            2           <none>          7m15s

Once the number of READY pods are equal, make sure the Cilium pre-flight deployment is also marked as READY 1/1. If it shows READY 0/1, consult the CNP Validation section and resolve issues with the deployment before continuing with the upgrade.

$ kubectl get deployment -n kube-system cilium-pre-flight-check -w
NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
cilium-pre-flight-check   1/1     1            0           12s

Clean up pre-flight check

Once the number of READY for the preflight DaemonSet is the same as the number of cilium pods running and the preflight Deployment is marked as READY 1/1 you can delete the cilium-preflight and proceed with the upgrade.

kubectl delete -f cilium-preflight.yaml

helm delete cilium-preflight --namespace=kube-system

Upgrading Cilium

During normal cluster operations, all Cilium components should run the same version. Upgrading just one of them (e.g., upgrading the agent without upgrading the operator) could result in unexpected cluster behavior. The following steps will describe how to upgrade all of the components from one stable release to a later stable release.

Warning

Read the full upgrade guide to understand all the necessary steps before performing them.

Do not upgrade to 1.13.0 before reading the section 1.13.3+ Upgrade Notes and completing the required steps. Skipping this step may lead to an non-functional upgrade.

Step 1: Upgrade to latest patch version

When upgrading from one minor release to another minor release, for example 1.x to 1.y, it is recommended to upgrade to the latest patch release for a Cilium release series first. The latest patch releases for each supported version of Cilium are here. Upgrading to the latest patch release ensures the most seamless experience if a rollback is required following the minor release upgrade. The upgrade guides for previous versions can be found for each minor version at the bottom left corner.

Step 2: Use Helm to Upgrade your Cilium deployment

Helm can be used to either upgrade Cilium directly or to generate a new set of YAML files that can be used to upgrade an existing deployment via kubectl. By default, Helm will generate the new templates using the default values files packaged with each new release. You still need to ensure that you are specifying the equivalent options as used for the initial deployment, either by specifying a them at the command line or by committing the values to a YAML file.

Note

Make sure you have Helm 3 installed. Helm 2 is no longer supported.

Setup Helm repository:

helm repo add cilium https://helm.cilium.io/

To minimize datapath disruption during the upgrade, the upgradeCompatibility option should be set to the initial Cilium version which was installed in this cluster.

Generate the required YAML file and deploy it:

helm template cilium/cilium --version 1.13.3 \
  --set upgradeCompatibility=1.X \
  --namespace kube-system \
  > cilium.yaml
kubectl apply -f cilium.yaml

Deploy Cilium release via Helm:

helm upgrade cilium cilium/cilium --version 1.13.3 \
  --namespace=kube-system \
  --set upgradeCompatibility=1.X

Note

Instead of using --set, you can also save the values relative to your deployment in a YAML file and use it to regenerate the YAML for the latest Cilium version. Running any of the previous commands will overwrite the existing cluster’s ConfigMap so it is critical to preserve any existing options, either by setting them at the command line or storing them in a YAML file, similar to:

agent: true
upgradeCompatibility: "1.8"
ipam:
  mode: "kubernetes"
k8sServiceHost: "API_SERVER_IP"
k8sServicePort: "API_SERVER_PORT"
kubeProxyReplacement: "strict"

You can then upgrade using this values file by running:

helm upgrade cilium cilium/cilium --version 1.13.3 \
  --namespace=kube-system \
  -f my-values.yaml

When upgrading from one minor release to another minor release using helm upgrade, do not use Helm’s --reuse-values flag. The --reuse-values flag ignores any newly introduced values present in the new release and thus may cause the Helm template to render incorrectly. Instead, if you want to reuse the values from your existing installation, save the old values in a values file, check the file for any renamed or deprecated values, and then pass it to the helm upgrade command as described above. You can retrieve and save the values from an existing installation with the following command:

helm get values cilium --namespace=kube-system -o yaml > old-values.yaml

The --reuse-values flag may only be safely used if the Cilium chart version remains unchanged, for example when helm upgrade is used to apply configuration changes without upgrading Cilium.

Step 3: Rolling Back

Occasionally, it may be necessary to undo the rollout because a step was missed or something went wrong during upgrade. To undo the rollout run:

kubectl rollout undo daemonset/cilium -n kube-system

helm history cilium --namespace=kube-system
helm rollback cilium [REVISION] --namespace=kube-system

This will revert the latest changes to the Cilium DaemonSet and return Cilium to the state it was in prior to the upgrade.

Note

When rolling back after new features of the new minor version have already been consumed, consult the Version Specific Notes to check and prepare for incompatible feature use before downgrading/rolling back. This step is only required after new functionality introduced in the new minor version has already been explicitly used by creating new resources or by opting into new features via the ConfigMap.

Version Specific Notes

This section documents the specific steps required for upgrading from one version of Cilium to another version of Cilium. There are particular version transitions which are suggested by the Cilium developers to avoid known issues during upgrade, then subsequently there are sections for specific upgrade transitions, ordered by version.

The table below lists suggested upgrade transitions, from a specified current version running in a cluster to a specified target version. If a specific combination is not listed in the table below, then it may not be safe. In that case, consider performing incremental upgrades between versions (e.g. upgrade from 1.10.x to 1.11.y first, and to 1.12.z only afterwards).

Current version	Target version	L3/L4 impact	L7 impact
`1.12.x`	`1.13.y`	Minimal to None	Clients must reconnect[1]
`1.11.x`	`1.12.y`	Minimal to None	Clients must reconnect[1]
`1.10.x`	`1.11.y`	Minimal to None	Clients must reconnect[1]

Annotations:

Clients must reconnect: Any traffic flowing via a proxy (for example, because an L7 policy is in place) will be disrupted during upgrade. Endpoints communicating via the proxy must reconnect to re-establish connections.

1.13.3+ Upgrade Notes

Egress Gateway policies now drop matching traffic when no gateway nodes can be found. Previously, traffic would be allowed without being rerouted towards an Egress Gateway.

1.13.2+ Upgrade Notes

When upgrading from Cilium <v1.13.1 or <v1.12.8 to Cilium >=v1.13.2 with IPsec enabled, packet drops may occur during the upgrade. These drops are expected to stop as soon as the Cilium agent is ready. IPsec error counters XfrmInNoStates and XfrmOutPolBlock may increase as a result of these drops.
There is a known issue (GitHub issue 24502) with CiliumNetworkPolicies that makes the kube-apiserver entity unreliable. Until this is resolved, it is recommended to grant access to the apiserver by the special world entity. This bug is present from v1.13.0.

1.13.1 Upgrade Notes

In upgrades to Cilium v1.13.1 with IPsec enabled, the IPsec state is not refreshed, which causes dropped connections in the cluster. As such, we recommend staying at v1.13.0. This issue can be mitigated by either replacing workload nodes in the cluster (to get a fresh IPsec state) or by flushing the current state by running the following command on each node: ip xfrm state flush && ip xfrm policy flush.

1.13 Upgrade Notes

The code for the deprecated spec.eni.min-allocate, spec.eni.pre-allocate spec.eni.max-above-watermark fields has been removed, those fields are no longer functional. Please use their semantically equivalent spec.ipam replacements instead.
The kube-proxy replacement in DSR or Hybrid mode with tunneling causes failure upon cilium-agent start. In previous versions, cilium-agent automatically used SNAT mode when we set tunneling.
In the ENI IPAM mode, the default subnet in which ENIs are created has changed from the subnet (in the same VPC and AZ) with the most addresses available to the subnet in which the primary ENI of the node is attached. Note that this default only matters if no explicit selection of the subnet occurs, i.e. specifying subnet IDs or tags still takes precedence.
NodeExternalIP of the local node is now correctly included into the host entity (it used to belong to the world entity).
The scope of the policy_implementation_delay Prometheus metric has been expanded to cover the full interval from when a policy is first received from a cilium-agent, to when the policy has been applied to endpoints. In previous versions, policy_implementation_delay only covered the work done by the daemon subsystem to implement the policy. As a result, users may notice an expected increase in policy_implementation_delay after upgrading.

Removed Options

The ineffective disable-conntrack, endpoint-interface-name-prefix options deprecated in version 1.12 have been removed.
The host-reachable-services-protos option deprecated in version v1.12 has been removed.
The probe option of kube-proxy-replacement deprecated in version v1.12 has been removed. Users of the probe option are advised either to use strict or partial with individual options configured. Please refer to Kubernetes Without kube-proxy for more info.
The CiliumEgressNATPolicy CRD deprecated in version 1.12 has been removed. It is superseded by the CiliumEgressGatewayPolicy CRD.
The pprof, pprof-port flags for cilium-operator have been renamed to operator-pprof and operator-pprof-port respectively.

Deprecated Options

The force-local-policy-eval-at-source option is deprecated and will be removed in 1.14.
The sockops-enable option is deprecated and will be removed in 1.14.

Added Metrics

cilium_operator_allocation_duration_seconds
cilium_operator_release_duration_seconds
httpV2, an updated version of the existing http metrics.
cilium_operator_ipam_interface_candidates
cilium_operator_ipam_empty_interface_slots

Modified Metrics

hubble_policy_verdicts_total now lists L7 flows. The match label has value l7/<l7_proto> after the detected L7 protocol of the flow (for example: l7/http).
Values for the reason label have been updated in hubble_drop_total metric. Please see the API documentation for the complete list of drop reasons.

Deprecated Metrics

http is deprecated. Please use httpV2 instead.
cilium_operator_ipam_available_interfaces is deprecated. Please use cilium_operator_ipam_interface_candidates and cilium_operator_ipam_empty_interface_slots instead.

Removed Metrics/Labels

cilium_operator_ipam_available is removed. Please use cilium_operator_ipam_interface_candidates and cilium_operator_ipam_empty_interface_slots instead.
cilium_operator_ipam_allocation_ops is removed. Please use cilium_operator_ipam_ip_allocation_ops instead.
cilium_operator_ipam_release_ops is removed. Please use cilium_operator_ipam_ip_release_ops instead.
The label of status in cilium_operator_ipam_interface_creation_ops is removed.
cilium_node_neigh_arping_requests_total is removed. The counter was ineffective since the v1.11.0.

Helm Options

The way Linux capabilities are configured has been revamped in this release. All capabilities of every container in the cilium-agent DaemonSet is configured from Helm’s values, defaulting to the old behavior. If you have not been using securityContext.extraCapabilities you do not need to do anything. If you were leveraging securityContext.extraCapabilities, you need to review securityContext.capabilities.cilium_agent.
bpf.hostLegacyRouting will be set to true automatically if cni.chainingMode is set to any other value than none (default)
The top-level pprof section now only configures pprof for cilium agent. The cilium-operator pprof configuration is now managed via the operator.pprof section. Additionally, a``hubble.relay.pprof`` section has been added.
All pprof configuration now support configuring the pprof listen address, defaulting to localhost.
The hubble.peerService.enabled value is deprecated. Currently true by default, Cilium v1.14 will remove the option to set it to false as support for Hubble Relay to query the Peer Service through the Hubble local UNIX domain socket will be removed and the Kubernetes peer-svc mandatory when Hubble Relay is enabled. Users overriding hubble.peerService.enabled to false are encouraged to migrate to true with the Cilium v1.13 release.

CRD Changes

CiliumBGPLoadBalancerIPPool CRD has been renamed to CiliumLoadBalancerIPPool.

Deprecated API Fields

trafficPolicy has been renamed to extTrafficPolicy in ServiceSpec.flags and ServiceUpsertNotification, in order to emphasize the distinction between the external and internal traffic policies. The old name remains for backward compatibility.

Earlier Upgrade Notes

For upgrades from earlier releases, see the upgrade notes from the previous version.

Advanced

Upgrade Impact

Upgrades are designed to have minimal impact on your running deployment. Networking connectivity, policy enforcement and load balancing will remain functional in general. The following is a list of operations that will not be available during the upgrade:

API aware policy rules are enforced in user space proxies and are currently running as part of the Cilium pod unless Cilium is configured to run in Istio mode. Upgrading Cilium will cause the proxy to restart which will result in a connectivity outage and connection to be reset.
Existing policy will remain effective but implementation of new policy rules will be postponed to after the upgrade has been completed on a particular node.
Monitoring components such as cilium monitor will experience a brief outage while the Cilium pod is restarting. Events are queued up and read after the upgrade. If the number of events exceeds the event buffer size, events will be lost.

Rebasing a ConfigMap

This section describes the procedure to rebase an existing ConfigMap to the template of another version.

Export the current ConfigMap

$ kubectl get configmap -n kube-system cilium-config -o yaml --export > cilium-cm-old.yaml
$ cat ./cilium-cm-old.yaml
apiVersion: v1
data:
  clean-cilium-state: "false"
  debug: "true"
  disable-ipv4: "false"
  etcd-config: |-
    ---
    endpoints:
    - https://192.168.60.11:2379
    #
    # In case you want to use TLS in etcd, uncomment the 'trusted-ca-file' line
    # and create a kubernetes secret by following the tutorial in
    # https://cilium.link/etcd-config
    trusted-ca-file: '/var/lib/etcd-secrets/etcd-client-ca.crt'
    #
    # In case you want client to server authentication, uncomment the following
    # lines and add the certificate and key in cilium-etcd-secrets below
    key-file: '/var/lib/etcd-secrets/etcd-client.key'
    cert-file: '/var/lib/etcd-secrets/etcd-client.crt'
kind: ConfigMap
metadata:
  creationTimestamp: null
  name: cilium-config
  selfLink: /api/v1/namespaces/kube-system/configmaps/cilium-config

In the ConfigMap above, we can verify that Cilium is using debug with true, it has a etcd endpoint running with TLS, and the etcd is set up to have client to server authentication.

Generate the latest ConfigMap

helm template cilium \
  --namespace=kube-system \
  --set agent.enabled=false \
  --set config.enabled=true \
  --set operator.enabled=false \
  > cilium-configmap.yaml

Add new options

Add the new options manually to your old ConfigMap, and make the necessary changes.

In this example, the debug option is meant to be kept with true, the etcd-config is kept unchanged, and monitor-aggregation is a new option, but after reading the Version Specific Notes the value was kept unchanged from the default value.

After making the necessary changes, the old ConfigMap was migrated with the new options while keeping the configuration that we wanted:

$ cat ./cilium-cm-old.yaml
apiVersion: v1
data:
  debug: "true"
  disable-ipv4: "false"
  # If you want to clean cilium state; change this value to true
  clean-cilium-state: "false"
  monitor-aggregation: "medium"
  etcd-config: |-
    ---
    endpoints:
    - https://192.168.60.11:2379
    #
    # In case you want to use TLS in etcd, uncomment the 'trusted-ca-file' line
    # and create a kubernetes secret by following the tutorial in
    # https://cilium.link/etcd-config
    trusted-ca-file: '/var/lib/etcd-secrets/etcd-client-ca.crt'
    #
    # In case you want client to server authentication, uncomment the following
    # lines and add the certificate and key in cilium-etcd-secrets below
    key-file: '/var/lib/etcd-secrets/etcd-client.key'
    cert-file: '/var/lib/etcd-secrets/etcd-client.crt'
kind: ConfigMap
metadata:
  creationTimestamp: null
  name: cilium-config
  selfLink: /api/v1/namespaces/kube-system/configmaps/cilium-config

Apply new ConfigMap

After adding the options, manually save the file with your changes and install the ConfigMap in the kube-system namespace of your cluster.

$ kubectl apply -n kube-system -f ./cilium-cm-old.yaml

As the ConfigMap is successfully upgraded we can start upgrading Cilium DaemonSet and RBAC which will pick up the latest configuration from the ConfigMap.

Migrating from kvstore-backed identities to Kubernetes CRD-backed identities

Beginning with cilium 1.6, Kubernetes CRD-backed security identities can be used for smaller clusters. Along with other changes in 1.6 this allows kvstore-free operation if desired. It is possible to migrate identities from an existing kvstore deployment to CRD-backed identities. This minimizes disruptions to traffic as the update rolls out through the cluster.

Affected versions

Cilium 1.6 deployments using kvstore-backend identities

Mitigation

When identities change, existing connections can be disrupted while cilium initializes and synchronizes with the shared identity store. The disruption occurs when new numeric identities are used for existing pods on some instances and others are used on others. When converting to CRD-backed identities, it is possible to pre-allocate CRD identities so that the numeric identities match those in the kvstore. This allows new and old cilium instances in the rollout to agree.

The steps below show an example of such a migration. It is safe to re-run the command if desired. It will identify already allocated identities or ones that cannot be migrated. Note that identity 34815 is migrated, 17003 is already migrated, and 11730 has a conflict and a new ID allocated for those labels.

The steps below assume a stable cluster with no new identities created during the rollout. Once a cilium using CRD-backed identities is running, it may begin allocating identities in a way that conflicts with older ones in the kvstore.

The cilium preflight manifest requires etcd support and can be built with:

helm template cilium \
  --namespace=kube-system \
  --set preflight.enabled=true \
  --set agent.enabled=false \
  --set config.enabled=false \
  --set operator.enabled=false \
  --set etcd.enabled=true \
  --set etcd.ssl=true \
  > cilium-preflight.yaml
kubectl create -f cilium-preflight.yaml

Example migration

$ kubectl exec -n kube-system cilium-pre-flight-check-1234 -- cilium preflight migrate-identity
INFO[0000] Setting up kvstore client
INFO[0000] Connecting to etcd server...                  config=/var/lib/cilium/etcd-config.yml endpoints="[https://192.168.60.11:2379]" subsys=kvstore
INFO[0000] Setting up kubernetes client
INFO[0000] Establishing connection to apiserver          host="https://192.168.60.11:6443" subsys=k8s
INFO[0000] Connected to apiserver                        subsys=k8s
INFO[0000] Got lease ID 29c66c67db8870c8                 subsys=kvstore
INFO[0000] Got lock lease ID 29c66c67db8870ca            subsys=kvstore
INFO[0000] Successfully verified version of etcd endpoint  config=/var/lib/cilium/etcd-config.yml endpoints="[https://192.168.60.11:2379]" etcdEndpoint="https://192.168.60.11:2379" subsys=kvstore version=3.3.13
INFO[0000] CRD (CustomResourceDefinition) is installed and up-to-date  name=CiliumNetworkPolicy/v2 subsys=k8s
INFO[0000] Updating CRD (CustomResourceDefinition)...    name=v2.CiliumEndpoint subsys=k8s
INFO[0001] CRD (CustomResourceDefinition) is installed and up-to-date  name=v2.CiliumEndpoint subsys=k8s
INFO[0001] Updating CRD (CustomResourceDefinition)...    name=v2.CiliumNode subsys=k8s
INFO[0002] CRD (CustomResourceDefinition) is installed and up-to-date  name=v2.CiliumNode subsys=k8s
INFO[0002] Updating CRD (CustomResourceDefinition)...    name=v2.CiliumIdentity subsys=k8s
INFO[0003] CRD (CustomResourceDefinition) is installed and up-to-date  name=v2.CiliumIdentity subsys=k8s
INFO[0003] Listing identities in kvstore
INFO[0003] Migrating identities to CRD
INFO[0003] Skipped non-kubernetes labels when labelling ciliumidentity. All labels will still be used in identity determination  labels="map[]" subsys=crd-allocator
INFO[0003] Skipped non-kubernetes labels when labelling ciliumidentity. All labels will still be used in identity determination  labels="map[]" subsys=crd-allocator
INFO[0003] Skipped non-kubernetes labels when labelling ciliumidentity. All labels will still be used in identity determination  labels="map[]" subsys=crd-allocator
INFO[0003] Migrated identity                             identity=34815 identityLabels="k8s:class=tiefighter;k8s:io.cilium.k8s.policy.cluster=default;k8s:io.cilium.k8s.policy.serviceaccount=default;k8s:io.kubernetes.pod.namespace=default;k8s:org=empire;"
WARN[0003] ID is allocated to a different key in CRD. A new ID will be allocated for the this key  identityLabels="k8s:class=deathstar;k8s:io.cilium.k8s.policy.cluster=default;k8s:io.cilium.k8s.policy.serviceaccount=default;k8s:io.kubernetes.pod.namespace=default;k8s:org=empire;" oldIdentity=11730
INFO[0003] Reusing existing global key                   key="k8s:class=deathstar;k8s:io.cilium.k8s.policy.cluster=default;k8s:io.cilium.k8s.policy.serviceaccount=default;k8s:io.kubernetes.pod.namespace=default;k8s:org=empire;" subsys=allocator
INFO[0003] New ID allocated for key in CRD               identity=17281 identityLabels="k8s:class=deathstar;k8s:io.cilium.k8s.policy.cluster=default;k8s:io.cilium.k8s.policy.serviceaccount=default;k8s:io.kubernetes.pod.namespace=default;k8s:org=empire;" oldIdentity=11730
INFO[0003] ID was already allocated to this key. It is already migrated  identity=17003 identityLabels="k8s:class=xwing;k8s:io.cilium.k8s.policy.cluster=default;k8s:io.cilium.k8s.policy.serviceaccount=default;k8s:io.kubernetes.pod.namespace=default;k8s:org=alliance;"

Note

It is also possible to use the --k8s-kubeconfig-path and --kvstore-opt cilium CLI options with the preflight command. The default is to derive the configuration as cilium-agent does.

cilium preflight migrate-identity --k8s-kubeconfig-path /var/lib/cilium/cilium.kubeconfig --kvstore etcd --kvstore-opt etcd.config=/var/lib/cilium/etcd-config.yml

Once the migration is complete, confirm the endpoint identities match by listing the endpoints stored in CRDs and in etcd:

$ kubectl get ciliumendpoints -A # new CRD-backed endpoints
$ kubectl exec -n kube-system cilium-1234 -- cilium endpoint list # existing etcd-backed endpoints

Clearing CRD identities

If a migration has gone wrong, it possible to start with a clean slate. Ensure that no cilium instances are running with identity-allocation-mode crd and execute:

$ kubectl delete ciliumid --all

CNP Validation

Running the CNP Validator will make sure the policies deployed in the cluster are valid. It is important to run this validation before an upgrade so it will make sure Cilium has a correct behavior after upgrade. Avoiding doing this validation might cause Cilium from updating its NodeStatus in those invalid Network Policies as well as in the worst case scenario it might give a false sense of security to the user if a policy is badly formatted and Cilium is not enforcing that policy due a bad validation schema. This CNP Validator is automatically executed as part of the pre-flight check Running pre-flight check (Required).

Start by deployment the cilium-pre-flight-check and check if the Deployment shows READY 1/1, if it does not check the pod logs.

$ kubectl get deployment -n kube-system cilium-pre-flight-check -w
NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
cilium-pre-flight-check   0/1     1            0           12s

$ kubectl logs -n kube-system deployment/cilium-pre-flight-check -c cnp-validator --previous
level=info msg="Setting up kubernetes client"
level=info msg="Establishing connection to apiserver" host="https://172.20.0.1:443" subsys=k8s
level=info msg="Connected to apiserver" subsys=k8s
level=info msg="Validating CiliumNetworkPolicy 'default/cidr-rule': OK!
level=error msg="Validating CiliumNetworkPolicy 'default/cnp-update': unexpected validation error: spec.labels: Invalid value: \"string\": spec.labels in body must be of type object: \"string\""
level=error msg="Found invalid CiliumNetworkPolicy"

In this example, we can see the CiliumNetworkPolicy in the default namespace with the name cnp-update is not valid for the Cilium version we are trying to upgrade. In order to fix this policy we need to edit it, we can do this by saving the policy locally and modify it. For this example it seems the .spec.labels has set an array of strings which is not correct as per the official schema.

$ kubectl get cnp -n default cnp-update -o yaml > cnp-bad.yaml
$ cat cnp-bad.yaml
  apiVersion: cilium.io/v2
  kind: CiliumNetworkPolicy
  [...]
  spec:
    endpointSelector:
      matchLabels:
        id: app1
    ingress:
    - fromEndpoints:
      - matchLabels:
          id: app2
      toPorts:
      - ports:
        - port: "80"
          protocol: TCP
    labels:
    - custom=true
  [...]

To fix this policy we need to set the .spec.labels with the right format and commit these changes into Kubernetes.

$ cat cnp-bad.yaml
  apiVersion: cilium.io/v2
  kind: CiliumNetworkPolicy
  [...]
  spec:
    endpointSelector:
      matchLabels:
        id: app1
    ingress:
    - fromEndpoints:
      - matchLabels:
          id: app2
      toPorts:
      - ports:
        - port: "80"
          protocol: TCP
    labels:
    - key: "custom"
      value: "true"
  [...]
$
$ kubectl apply -f ./cnp-bad.yaml

After applying the fixed policy we can delete the pod that was validating the policies so that Kubernetes creates a new pod immediately to verify if the fixed policies are now valid.

$ kubectl delete pod -n kube-system -l k8s-app=cilium-pre-flight-check-deployment
pod "cilium-pre-flight-check-86dfb69668-ngbql" deleted
$ kubectl get deployment -n kube-system cilium-pre-flight-check
NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
cilium-pre-flight-check   1/1     1            1           55m
$ kubectl logs -n kube-system deployment/cilium-pre-flight-check -c cnp-validator
level=info msg="Setting up kubernetes client"
level=info msg="Establishing connection to apiserver" host="https://172.20.0.1:443" subsys=k8s
level=info msg="Connected to apiserver" subsys=k8s
level=info msg="Validating CiliumNetworkPolicy 'default/cidr-rule': OK!
level=info msg="Validating CiliumNetworkPolicy 'default/cnp-update': OK!
level=info msg="All CCNPs and CNPs valid!"

Once they are valid you can continue with the upgrade process. Clean up pre-flight check