mirror of
https://github.com/openshift/installer.git
synced 2026-02-05 15:47:14 +01:00
95 lines
5.3 KiB
Markdown
95 lines
5.3 KiB
Markdown
# Limits
|
|
|
|
You can find a comprehensive list of the default AWS service limits published here:
|
|
|
|
[AWS Service Limits][service-limits]
|
|
|
|
Below, we'll identify OpenShift cluster needs and how those impact some of those limits.
|
|
|
|
## S3
|
|
|
|
There is a default limit of 100 S3 buckets per account. The installation creates a bucket temporarily. Also, the
|
|
registry component creates a permanent bucket. This will limit the number of clusters per account to 99 initially. To
|
|
support additional clusters, you must open a support case with AWS.
|
|
|
|
## VPC
|
|
|
|
Each cluster creates its own VPC. The default limit of VPCs per region is 5 and will allow 5 clusters. To have more
|
|
than 5 clusters, you will need to increase this limit.
|
|
|
|
Each cluster also creates a VPC Gateway Endpoint for a stable connection to S3. The default limit of VPC Gateway
|
|
Endpoints per region is 20 and will allow 20 clusters. To have more than 20 clusters, you will need to increase this
|
|
limit.
|
|
|
|
## Elastic Network Interfaces (ENI)
|
|
|
|
The default installation creates 21 + the number of availability zones of ENIs (e.g. 21 + 3 = 24 ENIs for a three-zone cluster).
|
|
The default limit per region is 350. Additional ENIs are created for additional machines and elastic load balancers
|
|
created by cluster usage and deployed workloads. A service limit increase here may be required to satisfy the needs of
|
|
additional clusters and deployed workloads.
|
|
|
|
## Elastic IP (EIP)
|
|
|
|
By default, the installer distributes control-plane and compute machines across [all availability zones within a region][availability-zones] to provision the cluster in a highly available configuration.
|
|
Please see [this map][az-map] for a current region map with availability zone count.
|
|
We recommend selecting regions with 3 or more availability zones.
|
|
You can [provide an install-config](../overview.md#multiple-invocations) to [configure](customization.md) the installer to use specific zones to override that default.
|
|
|
|
The installer creates a public and private subnet for each configured availability zone.
|
|
In each private subnet, a separate [NAT Gateway][nat-gateways] is created and requires a separate [EC2-VPC Elastic IP (EIP)][elastic-ip].
|
|
The default limit of 5 is sufficient for a single cluster, unless you have configured your cluster to use more than five zones.
|
|
For multiple clusters, a higher limit will likely be required (and will certainly be required to support more than five clusters, even if they are each single-zone clusters).
|
|
|
|
### Example: Using North Virginia (us-east-1)
|
|
|
|
North Virginia (us-east-1) has six availability zones, so a higher limit is required unless you configure your cluster to use fewer zones.
|
|
To support the default, all-zone installation, please submit a limit increase for VPC Elastic IPs similar to the following in the support dashboard (to create more than one cluster, a higher limit will be necessary):
|
|
|
|
|
|
|
|
## NAT Gateway
|
|
|
|
The default limit for NAT Gateways is 5 per availability zone. This is sufficient for up to 5 clusters in a dedicated
|
|
account. If you intend to create more than 5 clusters, you will need to request an increase to this limit.
|
|
|
|
## VPC Gateway
|
|
|
|
The default limit of VPC Gateways (for S3 access) is 20. Each cluster will create a single S3 gateway endpoint within
|
|
the new VPC. If you intend to create more than 20 clusters, you will need to request an increase to this limit.
|
|
|
|
## Security Groups
|
|
|
|
Each cluster creates distinct security groups. The default limit of 2,500 for new accounts allows for many clusters
|
|
to be created. The security groups which exist after the default install are:
|
|
|
|
1. VPC default
|
|
1. Master
|
|
1. Worker
|
|
1. Router/Ingress
|
|
|
|
## vCPU Limits
|
|
|
|
By default, a cluster will create:
|
|
|
|
* One m4.large bootstrap machine (2 vCPUs but removed after install)
|
|
* Three m5.xlarge master nodes (4 vCPUs each).
|
|
* Three m5.large worker nodes (2 vCPUs each).
|
|
|
|
Currently, these vCPU counts are not within a new account's default limit. The default limit is 1 but for all these instances you will need 20. To increase the limit you have to [contact the AWS support](https://console.aws.amazon.com/support/cases?#/create?issueType=service-limit-increase&limitType=ec2-instances).
|
|
If you intend to start with a higher number of workers, enable autoscaling and large workloads
|
|
or a different instance type, please ensure you have the necessary remaining vCPU count within the vCPU
|
|
limit to satisfy the need. To calculate the vCPU limit you can use the limits calculator in the EC2 console (EC2 -> Limits -> Limits calculator).
|
|
|
|
## Elastic Load Balancing (ELB/NLB)
|
|
|
|
By default, each cluster will create 2 network load balancers for the master API server (1 internal, 1 external) and a
|
|
single classic elastic load balancer for the router. Additional Kubernetes LoadBalancer Service objects will create
|
|
additional [load balancers][load-balancing].
|
|
|
|
[availability-zones]: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-regions-availability-zones.html
|
|
[az-map]: https://aws.amazon.com/about-aws/global-infrastructure/
|
|
[elastic-ip]: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/elastic-ip-addresses-eip.html
|
|
[load-balancing]: https://aws.amazon.com/elasticloadbalancing/
|
|
[nat-gateways]: https://docs.aws.amazon.com/vpc/latest/userguide/vpc-nat-gateway.html
|
|
[service-limits]: https://docs.aws.amazon.com/general/latest/gr/aws_service_limits.html
|