Getting Started > Installing Gremlin on OpenShift 4

Installing Gremlin on OpenShift 4

If you have shareProcessNamespace enabled, process-focused experiments like Shutdown and Process Killer will affect all containers in the target pod. This can also include Memory experiments that are halted due to the OOMkiller. To mitigate this, use Process Killer to target the specific PID of the container you want to impact. Note that when the first process (PID 1) in this namespace terminates, Kubernetes will terminate all other processes in the pod.

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Pre-requisites

Download authentication keys

Gremlin requires authentication during installation. You will need to download your Gremlin certificate key-pair in order to connect to your Gremlin team. The downloaded zip contains two files: <team-name>-client.pub_cert.pem is the certificate and <team-name>-client.priv_key.pem is the private key. With the key pair extracted to your local system, export the following variables into a local shell, supplying the appropriate values.

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SELinux considerations

Gremlin's container targeting features require the Gremlin Agent to run with hostPID=true. OpenShift's container runtime CRI-O automatically runs hostPID containers with the spc_t SELinux process label. No custom SELinux profile installation is required.

Previous versions of Gremlin would allow hostPID=false and as a result required a custom SELinux module to grant the Gremlin agent access to system calls and file access. If you have installed a custom SELinux policy using Gremlin's 96-worker-gremlin-semodule MachineConfig, you should remove this MachineConfig and ensure the Gremlin Daemonset is installed with hostPID=true .

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Helm installation

To install with Helm, log into the OpenShift cluster and run the following:

This command uses the classic Gremlin Helm repository. To pull the chart from Gremlin's OCI registry instead, see Note on using the Gremlin Helm repository.

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Run attacks

You can now run experiments on your cluster, including Kubernetes experiments. For step-by-step instructions, see How to run an experiment.

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Troubleshooting

For common issues and solutions, see Troubleshooting Gremlin on OpenShift.

Installing the Gremlin Agent

Authenticating the Gremlin Agent