FAQ
Answers to the most frequently asked questions about centron and Kubernetes – from costs and billing, through the control plane and node pools, to scaling, upgrades and networking. For a systematic approach to troubleshooting, see Troubleshooting.
Costs and billing
How much does the Control Plane cost?
The control plane is included in the price. You will only be billed for your worker nodes. Optionally, you can configure the control plane for high availability, charged per cluster per month – see the Kubernetes price overview.
How is billing carried out?
A fixed monthly price per plan applies. The stated price is fixed, regardless of utilisation. All prices are exclusive of VAT.
How much does a node cost?
The price depends on the instance type selected (C0 to C8). A full overview can be found under Pricing & Limits.
Are there any set-up costs involved in creating a cluster?
No, there are no set-up fees for Managed Kubernetes.
Control Plane
Do I have access to the control plane?
No. The control plane is operated entirely by centron. Access is provided exclusively via the Kubernetes API – SSH access is neither required nor provided for.
Can I add high availability at a later date?
Yes. A high-availability control plane can be enabled at any time in the Overview tab. However, once enabled, it cannot be removed.
What happens if the control plane fails?
Pods already running on the worker nodes will continue to operate. However, the Kubernetes API will be unavailable during this time: changes, rescheduling and scaling will not be possible.
Clusters and nodes
What is the minimum number of nodes a node pool should have?
We recommend at least 2 nodes per pool. During upgrades and maintenance work, nodes are restarted one after the other – if you only have one node, your application will be unavailable during this time.
Can I change the instance type of an existing node pool?
Not directly. Instead, create an additional node pool with the desired instance type, move your workloads to it, and then remove the old pool.
What is the difference between ‘Recycle’ and ‘Delete’?
Recycle restarts a node and replaces it – the size of the pool remains unchanged. Delete removes the node without providing a replacement. See Node Remediation.
Can a cluster contain more than one node pool?
Yes. Having multiple pools with different instance types makes it possible to run workloads of varying sizes within the same cluster.
Scaling
What is the difference between cluster autoscaling and horizontal pod autoscaling?
Cluster Autoscaling (CA) adjusts the number of nodes in a pool. Horizontal Pod Autoscaling (HPA) adjusts the number of pods for an application. The two complement each other: HPA launches additional pods, whilst CA provision the necessary nodes.
How do I enable autoscaling?
For each node pool, use the Set node pool to autoscale option, specifying the Minimum Nodes and Maximum Nodes. See Enable autoscaling.
Upgrades
Are updates installed automatically?
centron installs security-critical updates automatically. You can control whether all new patch versions are also installed automatically via the Settings tab, under Automatically upgrade minor version patches.
When are upgrades carried out?
Within your upgrade window – a four-hour period starting from the start time you have specified. You can configure the weekday and time in the Settings tab.
Will there be any downtime during an upgrade?
The nodes are updated sequentially on a rolling basis. With multiple nodes per pool and multiple replicas per application, your service remains available at all times. When Surge Upgrades are enabled, additional nodes are temporarily provisioned (up to 10), ensuring that capacity is maintained during the upgrade.
Network
Can I change the network zones at a later date?
No. Once the cluster has been created, the size of the pod and service networks cannot be changed. You should therefore plan these areas generously from the outset.
Is an Ingress Controller pre-installed?
No. To enable external access to HTTP services, you must install an Ingress Controller yourself. See Installing an Ingress Controller.
Where can I find my cluster’s network ranges?
In the Overview tab, under the Networking section – this is where the node, pod and service networks are listed.
Location and Data Protection
Where is my data processed?
Exclusively at the centron data centre in Hallstadt near Bamberg, Germany (Bamberg | Datacentre 1 | BBG1 region).
Delete cluster
What happens when a cluster is deleted?
Deletion is permanent. The cluster and all worker nodes will be removed, and all workloads will be terminated. Please back up or migrate your data beforehand. You must enter the cluster name to confirm. See Delete cluster.