Chapter 2. Red Hat Quay prerequisites
Before deploying Red Hat Quay, you must provision image storage, a database, and Redis.
2.1. Image storage backend
Red Hat Quay stores all binary blobs in its storage backend.
- Local storage
- Red Hat Quay can work with local storage, however this should only be used for proof of concept or test setups, as the durability of the binary blobs cannot be guaranteed.
- HA storage setup
For a Red Hat Quay HA deployment, you must provide HA image storage, for example:
- Red Hat OpenShift Data Foundation, previously known as Red Hat OpenShift Container Storage, is software-defined storage for containers. Engineered as the data and storage services platform for OpenShift Container Platform, Red Hat OpenShift Data Foundation helps teams develop and deploy applications quickly and efficiently across clouds. More information can be found at https://www.redhat.com/en/technologies/cloud-computing/openshift-data-foundation.
- Ceph Object Gateway (also called RADOS Gateway) is an example of a storage solution that can provide the the object storage needed by Red Hat Quay. Detailed instructions on how to use Ceph storage as a highly available storage backend can be found in the Quay High Availability Guide. Further information about Red Hat Ceph Storage and HA setups can be found in the Red Hat Ceph Storage Architecture Guide
- Geo-replication
- Local storage cannot be used for geo-replication, so a supported on premise or cloud based object storage solution must be deployed. Localized image storage is provided in each region and image pulls are served from the closest available storage engine. Container image pushes are written to the preferred storage engine for the Red Hat Quay instance, and will then be replicated, in the background, to the other storage engines. This requires the image storage to be accessible from all regions.
2.1.1. Supported image storage engines
Red Hat Quay supports the following on premise storage types:
- Ceph/Rados RGW
- OpenStack Swift
- Red Hat OpenShift Data Foundation 4 (through NooBaa)
Red Hat Quay supports the following public cloud storage engines:
- Amazon Web Services (AWS) S3
- Google Cloud Storage
- Azure Blob Storage
2.1.2. Unsupported image storage engines
Currently, Hitachi HCP is unsupported. Because every implementation of S3 is different, problems have arisen with Hitachi HCP in the past. Hitachi HCP might work if Ceph/RADOS drivers are used, however, Red Hat Quay cannot guarantee that it works properly in all scenarios and is therefor unsupported.
2.2. Database backend
Red Hat Quay stores all of its configuration information in the config.yaml file. Registry metadata, for example, user information, robot accounts, team, permissions, organizations, images, tags, manifests, etc. are stored inside of the database backend. Logs can be pushed to ElasticSearch if required. PostgreSQL is the preferred database backend because it can be used for both Red Hat Quay and Clair.
A future version of Red Hat Quay will remove support for using MySQL and MariaDB as the database backend, which has been deprecated since the Red Hat Quay 3.6 release. Until then, MySQL is still supported according to the support matrix, but will not receive additional features or explicit testing coverage. The Red Hat Quay Operator supports only PostgreSQL deployments when the database is managed. If you want to use MySQL, you must deploy it manually and set the database component to managed: false.
Deploying Red Hat Quay in a highly available (HA) configuration requires that your database services are provisioned for high availability. If Red Hat Quay is running on public cloud infrastructure, it is recommended that you use the PostgreSQL services provided by your cloud provider, however MySQL is also supported.
Geo-replication requires a single, shared database that is accessible from all regions.
2.3. Redis
Red Hat Quay stores builder logs inside a Redis cache. Because the data stored is ephemeral, Redis does not need to be highly available even though it is stateful.
If Redis fails, you will lose access to build logs, builders, and the garbage collector service. Additionally, user events will be unavailable.
You can use a Redis image from the Red Hat Software Collections or from any other source you prefer.
