Prepare Linux (preview)
The article describes how to prepare Linux using AKS enabled by Azure Arc, Edge Essentials, or Ubuntu.
Note
The minimum supported Linux kernel version is 5.1. At this time, there are known issues with 6.4 and 6.2.
Prerequisites
Note
Azure Container Storage enabled by Azure Arc is only available in the following regions: East US, East US 2, West US, West US 2, West US 3, North Europe, West Europe.
Arc-connected Kubernetes cluster
These instructions assume that you already have an Arc-connected Kubernetes cluster. To connect an existing Kubernetes cluster to Azure Arc, see these instructions.
If you want to use Azure Container Storage enabled by Azure Arc with Azure IoT Operations, follow the instructions to create a cluster for Azure IoT Operations.
Use Ubuntu 22.04 on Standard D8s v3 machines with three SSDs attached for more storage.
Single-node and multi-node clusters
A single-node cluster is commonly used for development or testing purposes due to its simplicity in setup and minimal resource requirements. These clusters offer a lightweight and straightforward environment for developers to experiment with Kubernetes without the complexity of a multi-node setup. Additionally, in situations where resources such as CPU, memory, and storage are limited, a single-node cluster is more practical. Its ease of setup and minimal resource requirements make it a suitable choice in resource-constrained environments.
However, single-node clusters come with limitations, mostly in the form of missing features, including their lack of high availability, fault tolerance, scalability, and performance.
A multi-node Kubernetes configuration is typically used for production, staging, or large-scale scenarios because of features such as high availability, fault tolerance, scalability, and performance. A multi-node cluster also introduces challenges and trade-offs, including complexity, overhead, cost, and efficiency considerations. For example, setting up and maintaining a multi-node cluster requires extra knowledge, skills, tools, and resources (network, storage, compute). The cluster must handle coordination and communication among nodes, leading to potential latency and errors. Additionally, running a multi-node cluster is more resource-intensive and is costlier than a single-node cluster. Optimization of resource usage among nodes is crucial for maintaining cluster and application efficiency and performance.
In summary, a single-node Kubernetes cluster might be suitable for development, testing, and resource-constrained environments. A multi-node cluster is more appropriate for production deployments, high availability, scalability, and scenarios in which distributed applications are a requirement. This choice ultimately depends on your specific needs and goals for your deployment.
Minimum hardware requirements
Single-node or 2-node cluster
- Standard_D8ds_v5 VM recommended
- Equivalent specifications per node:
- 4 CPUs
- 16 GB RAM
Multi-node cluster
- Standard_D8as_v5 VM recommended
- Equivalent specifications per node:
- 8 CPUs
- 32 GB RAM
32 GB RAM serves as a buffer; however, 16 GB RAM should suffice. Edge Essentials configurations require 8 CPUs with 10 GB RAM per node, making 16 GB RAM the minimum requirement.
Minimum storage requirements
Edge Volumes requirements
When you use the fault tolerant storage option, Edge Volumes allocates disk space out of a fault tolerant storage pool, which is made up of the storage exported by each node in the cluster.
The storage pool is configured to use 3-way replication to ensure fault tolerance. When an Edge Volume is provisioned, it allocates disk space from the storage pool, and allocates storage on 3 of the replicas.
For example, in a 3-node cluster with 20 GB of disk space per node, the cluster has a storage pool of 60 GB. However, due to replication, it has an effective storage size of 20 GB.
When an Edge Volume is provisioned with a requested size of 10 GB, it allocates a reserved system volume (statically sized to 1 GB) and a data volume (sized to the requested volume size, for example 10 GB). The reserved system volume consumes 3 GB (3 x 1 GB) of disk space in the storage pool, and the data volume will consume 30 GB (3 x 10 GB) of disk space in the storage pool, for a total of 33 GB.
Cache Volumes requirements
Cache Volumes requires at least 4 GB per node of storage. For example, if you have a 3-node cluster, you need at least 12 GB of storage.
Next steps
To continue preparing Linux, see the following instructions for single-node or multi-node clusters: