常见问题解答 (FAQ)

问题

Q: If I do not have deployed Kubernetes clusters, can I use Chaos Mesh to create chaos experiments?

No. Instead, you could use chaosd to inject failures without kubernetes.

Q: I have deployed Chaos Mesh and created PodChaos experiments successfully, but I still failed in creating NetworkChaos/TimeChaos Experiment. The log is shown as below:

  1. 2020-06-18T02:49:15.160Z ERROR controllers.TimeChaos failed to apply chaos on all pods {"reconciler": "timechaos", "error": "rpc error: code = Unavailable desc = connection error: desc = \"transport: Error while dialing dial tcp xx.xx.xx.xx:xxxx: connect: connection refused\""}

The reason is that chaos-controller-manager failed to connect to chaos-daemon. You need to first check the Pod network and its policies.

If everything is in order, maybe you can use the hostNetwork parameter to fix this problem as follows:

Reference: https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/troubleshooting-kubeadm/#hostport-services-do-not-work

Q: The default administrator Google Cloud user account is forbidden to create chaos experiments. How to fix it?

The default administrator Google Cloud user cannot be checked by AdmissionReview. You need to create an administrator role and assign the role to your account to grant the privilege of creating chaos experiments to it. For example:

  1. kind: ClusterRole
  2. apiVersion: rbac.authorization.k8s.io/v1
  3. metadata:
  4.   name: role-cluster-manager-pdmas
  5. rules:
  6.   - apiGroups: ['']
  7.     resources: ['pods', 'namespaces']
  8.     verbs: ['get', 'watch', 'list']
  9.   - apiGroups:
  10.       - chaos-mesh.org
  11.     resources: ['*']
  12.     verbs: ['get', 'list', 'watch', 'create', 'delete', 'patch', 'update']
  13. ---
  14. kind: ClusterRoleBinding
  15. apiVersion: rbac.authorization.k8s.io/v1
  16. metadata:
  17.   name: cluster-manager-binding
  18.   namespace: chaos-testing
  19. subjects:
  20.   # Google Cloud user account
  21.   - kind: User
  22.     name: USER_ACCOUNT
  23. roleRef:
  24.   kind: ClusterRole
  25.   name: role-cluster-manager-pdmas
  26.   apiGroup: rbac.authorization.k8s.io

The USER_ACCOUNT above should be your Google Cloud user email.

Q: Daemon throws an error similar to version 1.41 is too new. The maximum supported API version is 1.39

This indicates that the maximum API version that the Docker daemon can accept is 1.39, but the client in chaos-daemon uses 1.41 by default. You can choose the following options to solve this problem:

  1. Upgrade your Docker to a newer version.
  2. Helm install/upgrade with --set chaosDaemon.env.DOCKER_API_VERSION=1.39.

DNSChaos

Q: While trying to run DNSChaos in OpenShift, the problems regarding authorization blocked the process

If the error message is similar to the following:

  1. Error creating: pods "chaos-dns-server-123aa56123-" is forbidden: unable to validate against any security context constraint: [spec.containers[0].securityContext.capabilities.add: Invalid value: "NET_BIND_SERVICE": capability may not be added]

You need to add the privileged Security Context Constraints (SCC) to the chaos-dns-server.

  1. oc adm policy add-scc-to-user privileged -n chaos-testing -z chaos-dns-server

安装

Q: While trying to install Chaos Mesh in OpenShift, the problems regarding authorization blocked the installation process

If the error message is similar to the following:

  1. Error creating: pods "chaos-daemon-" is forbidden: unable
  2.  to validate against any security context constraint: [spec.securityContext.hostNetwork:
  3.  Invalid value: true: Host network is not allowed to be used spec.securityContext.hostPID:
  4.  Invalid value: true: Host PID is not allowed to be used spec.securityContext.hostIPC:
  5.  Invalid value: true: Host IPC is not allowed to be used securityContext.runAsUser:
  6.  Invalid value: "hostPath": hostPath volumes are not allowed to be used spec.containers[0].securityContext.volumes[1]:
  7.  Invalid value: true: Host network is not allowed to be used spec.containers[0].securityContext.containers[0].hostPort:
  8.  Invalid value: 31767: Host ports are not allowed to be used spec.containers[0].securityContext.hostPID:
  9.  Invalid value: true: Host PID is not allowed to be used spec.containers[0].securityContext.hostIPC:
  10. ......]

You need to add privileged scc to default.

  1. oc adm policy add-scc-to-user privileged -n chaos-testing -z chaos-daemon

Q: Failed to install Chaos Mesh with the message: no matches for kind “CustomResourceDefinition” in version “apiextensions.k8s.io/v1”

This issue occurs when you install Chaos Mesh on Kubernetes v1.15 or an earlier version. We use apiextensions.k8s.io/v1 by default, but it was introduced in Kubernetes v1.16 on 2019-09-19.

When you install Chaos Mesh on Kubernetes lower than v1.16, you need to follow the below process:

  1. Manually create CRD through https://mirrors.chaos-mesh.org/<chaos-mesh-version>/crd-v1beta1.yaml.
  2. Add --validate=false. If the configuration is not added, compatibility issues with breaking changes with CRD might occur. For example, kubectl create -f https://mirrors.chaos-mesh.org/v2.1.0/crd-v1beta1.yaml --validate=false.
  3. Use Helm to finish the rest process of installation, and append --skip-crds with helm install command.

We suggest upgrading your Kubernetes cluster by referencing Kubernetes Version Skew Policy.