The number of databases is unlimited. The limiting factor is the available memory in the cluster, and the number of shards in the subscription. Note that the impact of the specific database configuration on the number of shards it consumes. For example: Enabling database replication, without enabling database clustering, creates two shards: a master shard and a replica shard. Enabling database clustering creates as many database shards as you configure. Enabling both database replication and database clustering creates double the number of database shards you configure. »

Command differences Some JSON commands work differently for Active-Active databases. JSON.CLEAR JSON.CLEAR resets JSON arrays and objects. It supports concurrent updates to JSON documents from different instances in an Active-Active database and allows the results to be merged. »

Conflict resolution rules With Active-Active databases, it’s possible for two different instances to try to run write operations on the same data at the same time. If this happens, conflicts can arise when the replicas attempt to sync these changes with each other. Conflict resolution rules determine how the database handles conflicting operations. There are two types of conflict resolution: Merge: The operations are associative. Merges the results of both operations. »

Versions 6.4.2 and later uses a new ValidatingWebhookConfiguration resource to replace redb-admission. To use newer releases, delete the old webhook resource and apply the new file. Delete the existing ValidatingWebhookConfiguration on the Kubernetes cluster (named redb-admission). kubectl delete ValidatingWebhookConfiguration redb-admission Apply the resource from the new file. kubectl apply -f deploy/admission/webhook.yaml »

Verify the admission-tls secret exists. kubectl get secret admission-tls The output should look similar to NAME TYPE DATA AGE admission-tls Opaque 2 2m43s Save the certificate to a local environment variable. CERT=`kubectl get secret admission-tls -o jsonpath='{.data.cert}'` Create a Kubernetes validating webhook, replacing <namespace> with the namespace where the REC was installed. The webhook.yaml template can be found in redis-enterprise-k8s-docs/admission sed 's/OPERATOR_NAMESPACE/<namespace>/g' webhook.yaml | kubectl create -f - Create a patch file for the Kubernetes validating webhook. »

Redis OSS Cluster API reduces access times and latency with near-linear scalability. The Redis OSS Cluster API provides a simple mechanism for Redis clients to know the cluster topology. Clients must first connect to the master node to get the cluster topology, and then they connect directly to the Redis proxy on each node that hosts a master shard. Note: You must use a client that supports the OSS cluster API to connect to a database that has the OSS cluster API enabled. »

If port 53 is in use, the installation fails. This can occur in default installations of Ubuntu 18.04 and 20.04 in which systemd-resolved (DNS server) is running. To prevent this issue, change the system configuration to make this port available before installation. Edit /etc/systemd/resolved.conf: sudo vi /etc/systemd/resolved.conf Add DNSStubListener=no as the last line in the file and save the file. Rename the current /etc/resolv.conf file: sudo mv /etc/resolv.conf /etc/resolv.conf.orig Create a symbolic link for /etc/resolv. »

If ports that Redis assigns to the database are being used by the operating system or other processes, the installation fails. Follow the relevant sections to configure required ports. For recommended and optional port configuration, see Network port configurations. »

To avoid port collision, update /etc/sysctl.conf to include: net.ipv4.ip_local_port_range = 30000 65535 »

To make sure that Redis Enterprise Software (RS) servers can pass necessary communications between them, we recommend that all RS servers have all of the ports listed here open between them. By default, the cluster assigns ports in the range of 10,000 - 19,999 to database endpoints. If you assign a specific port for a database when you create it, even outside of this range, the cluster only verifies that the assigned port is not already in use. »