Reviewed on 22 August 2024 • Published on 26 September 2023
On a managed Kubernetes service such as Kapsule or Kosmos, Scaleway is responsible for overseeing the Kubernetes control plane.
The control plane comprises multiple components that play a crucial role in cluster management, application scheduling, and cluster state maintenance.
These components encompass the control plane’s core elements, namely etcd, API server, scheduler, cloud controller, and controller manager.
Scaleway offers a range of Kubernetes control planes to cater to a wide range of use cases and to provide you with maximum flexibility.
Whether you are seeking a mutualized environment or a dedicated control plane, we provide a flexible offer to fit your infrastructure needs, which can be a differentiating advantage from other Kubernetes engine providers.
1 Each mutualized control plane can use up to 4 GB memory (RAM and swap).
The resource quotas for each offer are subject to potential evolutions over time, and this table will be modified accordingly.
The size of the etcd key value store is limited to 55 MB and 200 MB, for mutualized and dedicated control planes, respectively. You can view the usage of your control plane’s etcd in Cockpit.
You have the option of choosing the most suitable control plane type for your workload when setting up a Kubernetes Kapsule or Kubernetes Kosmos cluster.
The cost of the control plane varies depending on whether it is a shared or dedicated environment, and by the specific dedicated resources that you choose. Although indicated that the control planes are billed monthly in the Scaleway console, the billing for each control plane option is calculated on an hourly basis. Scaleway chooses to display a monthly billing for simplicity purposes.
The control plane within the Kubernetes architecture goes beyond being just another component; it acts as the central command that orchestrates the cluster’s activities. Comprising elements like the API server, etcd, scheduler, and controller manager, the control plane oversees critical operations including resource distribution, scheduling, health checks, and scaling. Making frequent modifications to the control plane can result in unintended repercussions, compatibility conflicts, and potential downtimes, directly impacting the overall dependability of the whole cluster. Therefore, it is imperative to handle the control plane with the utmost care and prudence to sustain a smoothly operating Kubernetes cluster.
When selecting a dedicated environment, you are committing to this plan for 30 calendar days. While the cluster is active, you retain the flexibility to shift their control plane among different types to better align with their workloads. However, certain conditions govern this migration process:
Upgrading to a higher tier will reset the commitment period to 30 calendar days.
Downgrading to a lower tier will not extend the commitment period.
Downgrading a cluster type is not allowed during the commitment period.
Once a dedicated control plane is no longer under commitment, you can freely migrate to a lower tier using the Scaleway console or command-line interface (CLI).
Important
Migrating to a lower tier will have some impact on key features. The allocated RAM resources will be reduced, the maximum number of nodes will be limited, and in the case of a mutualized control plane, the SLA (Service Level Agreement) will be revoked.
If a dedicated cluster is deleted, the commitment is automatically canceled, and there will be no further billing for this dedicated service.
In Scaleway’s managed Kubernetes offers, the size of the etcd key-value store is a critical factor that users must consider.
The etcd store is the backbone of Kubernetes, holding all cluster data and ensuring the smooth operation of the control plane. However, there are size limitations to be aware of:
Mutualized control planes: The etcd size is limited to 55 MB.
Dedicated control planes: The etcd size is increased to 200 MB.
These limitations exist to ensure the stability and performance of your Kubernetes clusters.
For users running complex applications or managing large volumes of data, opting for a dedicated control plane is advisable. This not only provides a more substantial etcd quota but also enhances overall cluster performance and reliability.
You can monitor the size of your control plane’s etcd using Cockpit, Scaleway’s intuitive management interface. This visibility helps in proactive management and ensures you remain within the allotted limits, avoiding potential disruptions.
Note
You can not downgrade your cluster’s control plane from a dedicated one to a mutualized control plane when your etcd quota exceeds the mutualized storage allowance.
During the lifecycle of a Kubernetes cluster, you have the flexibility to transition its control plane to a different type, whether it involves scaling up or scaling down, to align with their specific workloads.