| Supporting services such as NGINX, Prometheus, etc. | 2 | 4 vCPU, 15 GB memory | `n1-standard-4` | 7.75 vCPU, 25 GB memory |
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1. Nodes configuration is shown as it is forced to ensure pod vcpu / memory ratios and avoid scaling during **performance testing**.
In production deployments there is no need to assign pods to nodes. A minimum of three nodes in three different availability zones is strongly recommended to align with resilient cloud architecture practices.
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Next are the backend components that run on static compute VMs via Omnibus (or External PaaS
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1. Can be optionally run on reputable third-party external PaaS PostgreSQL solutions. Google Cloud SQL and AWS RDS are known to work, however Azure Database for PostgreSQL is [not recommended](https://gitlab.com/gitlab-org/quality/reference-architectures/-/issues/61) due to performance issues. Consul is primarily used for PostgreSQL high availability so can be ignored when using a PostgreSQL PaaS setup. However it is also used optionally by Prometheus for Omnibus auto host discovery.
2. Can be optionally run on reputable third-party external PaaS Redis solutions. Google Memorystore and AWS Elasticache are known to work.
3. Can be optionally run on reputable third-party load balancing services (LB PaaS). AWS ELB is known to work.
4. Should be run on reputable third party object storage (storage PaaS) for cloud implementations. Google Cloud Storage and AWS S3 are known to work.
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NOTE:
For all PaaS solutions that involve configuring instances, it is strongly recommended to implement a minimum of three nodes in three different availability zones to align with resilient cloud architecture practices.
```plantuml
@startuml 25k
card "Kubernetes via Helm Charts" as kubernetes {
card "**External Load Balancer**" as elb #6a9be7
together {
collections "**Webservice** x7" as gitlab #32CD32
collections "**Sidekiq** x4" as sidekiq #ff8dd1
}
card "**Prometheus + Grafana**" as monitor #7FFFD4
card "**Supporting Services**" as support
}
card "**Internal Load Balancer**" as ilb #9370DB
collections "**Consul** x3" as consul #e76a9b
card "Gitaly Cluster" as gitaly_cluster {
collections "**Praefect** x3" as praefect #FF8C00
collections "**Gitaly** x3" as gitaly #FF8C00
card "**Praefect PostgreSQL***\n//Non fault-tolerant//" as praefect_postgres #FF8C00
praefect -[#FF8C00]-> gitaly
praefect -[#FF8C00]> praefect_postgres
}
card "Database" as database {
collections "**PGBouncer** x3" as pgbouncer #4EA7FF
card "**PostgreSQL** (Primary)" as postgres_primary #4EA7FF
collections "**PostgreSQL** (Secondary) x2" as postgres_secondary #4EA7FF
pgbouncer -[#4EA7FF]-> postgres_primary
postgres_primary .[#4EA7FF]> postgres_secondary
}
card "redis" as redis {
collections "**Redis Persistent** x3" as redis_persistent #FF6347
collections "**Redis Cache** x3" as redis_cache #FF6347
collections "**Redis Persistent Sentinel** x3" as redis_persistent_sentinel #FF6347
