A multi-cluster mesh connects multiple clusters into a single service mesh. The topology of the mesh – how the different clusters are grouped into networks and how each cluster connects to the mesh – determines how the clusters connect to each other and how the pods, services, and workloads can access resources in other clusters.
Communication between clusters 🔗︎
In a multi-cluster mesh, every cluster belongs to a specific network. Clusters belonging to the same mesh can access the services of each other, but how this happens depends on which network the cluster belongs to.
- If the clusters belong to the same network, their pods can access each other directly over a flat network, without using a cluster gateway.
- If the clusters belong to different networks, the services of the cluster can be accessed only through the gateway of the cluster. Since Backyards assigns each cluster to its own network by default, this is the default behavior.
The networkName label of the cluster determines which network the cluster belongs to. By default, every cluster belongs to its own network, where the name of the network is the name of the cluster.
Note: If the name of the cluster cannot be used as a Kubernetes resource name (for example, because it contains the underscore or another special character), you must manually specify a name to use when you are attaching the cluster to the service mesh.
Otherwise, the following error occurs when you try to attach the cluster:
could not attach peer cluster: graphql: Secret "example-secret" is invalid: metadata.name: Invalid value: "gke_gcp-cluster_region": a DNS-1123 subdomain must consist of lower case alphanumeric characters, '-' or '.'**
You can specify the network of the cluster when you are attaching the cluster to the mesh.
Assigning clusters to different networks allows you to optimize the topology of your mesh network. Depending on your cloud provider, there might be differences in cross-cluster latencies and transfer costs between the different connection types.
CAUTION:To change the network of a cluster already attached to the mesh, you have to detach and then re-attach the cluster. Simply updating the
networkNamelabel is NOT enough.