- Getting Started
- Requirements
- Best Practices
- Installation
- Updating
- Identity Server
- High Availability Add-on
- Release Notes
- Hardware and Software Requirements
- Upgrading High Availability Add-on
- Troubleshooting startup errors
Hardware and Software Requirements
The hardware requirements for your High Availability Add-on (HAA) are different between development and production environments.
Item |
Minimum Requirements |
Recommended |
---|---|---|
HAA Nodes |
1 |
3+ |
RAM |
6 GB |
8 GB |
Storage (default path
/opt/redislabs )
|
10 GB |
20 GB |
While one node is sufficient for a development environment, three or an odd number of nodes are recommended in order to utilize the clustering features likely needed for your production environment.
Item |
Minimum Requirements |
Recommended |
---|---|---|
HAA Nodes |
3 |
3+ |
Cores per Node |
4 |
8+ |
RAM |
6 GB (15 GB for DR deployments) |
30+ GB |
Storage (default path
/opt/redislabs )
|
75 GB |
150+ GB |
Network |
1 G |
10+ G |
Port |
Protocol |
Description |
---|---|---|
1968 |
TCP |
Default port used for internal proxy traffic. |
3333-3344 36379-36380 |
TCP |
Default port ranges used for internal cluster traffic. |
8001 |
TCP |
Used for traffic from the application to the Discovery Service, if applicable. |
8443 |
TCP |
Used for
HTTPS access to the management UI.
|
8444,9080 |
TCP |
Default ports used for internal
nginx < - > cnm_http/cm traffic.
|
9081 |
TCP |
Default port used for internal CRDB (Conflict-free Replicated Database) traffic. |
8070-8071 |
TCP |
Used for metrics exported and managed by
nginx .
|
9443 |
TCP |
Recommended port for REST API traffic. |
10000-19999 |
TCP |
Port range for database traffic. By default, HAA uses port
10000 .
|
20000-29999 |
TCP |
Port range used for internal database shards traffic. |
53,5353 |
UDP |
Used for internal
DNS/mDNS traffic.
|
8002,8004,8006 |
TCP |
System health monitoring. |
ICMP |
Used to check connectivity between nodes. |
HAA only supports 64-bit operating systems and must be installed on a clean host with no other applications. All HAA nodes must be synchronized with the same NTP server.
The following table lists the OS versions that we tested and confirmed to be compatible with HAA. However, due to the high number of operating system updates and variations, we cannot test compatibility for each combination of HAA version and minor OS version. While we generally expect HAA to work correctly with newer minor OS versions that we did not test, we cannot guarantee compatibility.
If you plan to upgrade to a minor OS version that we do not list in the table, you must perform the upgrade in a testing environment before deploying in a production environment.
Platform |
Supported Versions |
---|---|
RHEL/CentOS 8 |
8.6, 8.8, 8.9 |
RHEL/CentOS 9 |
9.3 |
Ubuntu |
20.04 Server version is recommended for production installations. Desktop version is only recommended for development deployments. |
The HAA cluster needs three servers for a healthy operation.
Under normal circumstances, the HAA cluster servers have the following roles:
- one principal server – it holds a data shard, and it accepts read and write database operations from the outside world;
- one secondary server – it holds a copy of the data shard;
- one secondary server – it holds no data, it exists for quorum purposes only.
The HAA cluster supports a single server failure only.
- If one of the servers goes down, no matter which one, the HAA cluster continues working, and a warning is shown in the Web
management interface. You can find more information by running the
rlcheck
command, usually found in/opt/redislabs/bin
. You can also append--continue-on-error
to therlcheck
command. - If two servers fail, the HAA cluster fails as well, even if the principal server is still online.
Building an HAA cluster with more than three servers is possible but offers no real benefit.
There is no increase in the number of servers that can fail. In the case of a five-node HAA cluster, if the principal node and the secondary node keeping the data shard copy both fail, the entire cluster fails as well, and there is no data shard reallocation to other nodes.
HAA supports both IPv4 and IPv6. For more details on the support for multi-IP and IPv6, refer to Redis documentation.