4 ms·

How does this compare to other HA postgres products like stolon or Postgres-XL?

by eicnix 9y ago

vishesh92 9y ago
As per my understanding, Postgres-XL is not comparable to Patroni. Postgres-XL is comparable to PostgreSQL. Postgres-XL shards the data across multiple data nodes. Where as Patroni uses etcd, consul or zookeeper to provide HA for any Postgres cluster using replication (Data is written only to a single instance and replicated further). I think you meant Stolon. Stolon is quite comparable to Patroni and has more features than Patroni, but I am not sure how many people are using it. I found more resources for Patroni as compared to stolon.
- CyberDem0n 9y ago
  > Stolon is quite comparable to Patroni and has more features than Patron. Let me as a question, what feature Stolon has and Patroni doesn't? Can you give an example? From my side I can provide list of features available in Patroni, but not in Stolon. For example: * there is no way to do a controlled failover (switchover) in Stolon. * in Patroni it's possible to exclude some nodes from a leader race. * Patroni supports cascading replication * Patroni can take basebackup from replicas if they are marked with a special tag * it's even possible to configure Patroni to use a custom backup/recovery solution instead of pg_basebackup * Patroni can give you a hint that postgres must be restarted to apply some configuration changes * with Patroni it's even possible to schedule switchover or restart restart of postges on some specific time (for example 04:00 am, when traffic is minimal) * with Patroni you can control High-Availability / Durability ratio. I.e.: what to do if master postgres has crashed? Either you will try to start it back or failover to a replica. But start of a crashed postgres may take a long time. With Patroni you can configure that if postgres didn't started in some amount of seconds - please do failover. Stolon provides cloud-native deployment and Patroni doesn't? This is not really true. The main idea of Patroni is to be not dependent on some specific technologies. It can work as on bare-metal with the same success as on Kubernetes. It's very easy to build a custom solution with Patroni for your use-case. For example there is a Spilo project: https://github.com/zalando/spilo https://github.com/zalando/spilo, a docker image build with Patroni and wal-e for a cloud deployments.
  - vishesh92 9y ago
    Thanks for this. As I mentioned in previous comment, I couldn't find much about Stolon. One of things I likee in stolon is the proxy, it enforce connections to the right PostgreSQL master and forcibly closes connections to unelected masters. Which is not present in Patroni, but I guess it should be doable using consul's service discovery and dynamic DNS. (I am not sure if this can be done using etcd and zookeper).
    - CyberDem0n 9y ago
      Doesn't HAProxy provide such functionality? Patroni has REST API which can be used by HAProxy for a health-check. patroni:8008/master will return http status code 200 only if the node running as elected master patroni:8008/replica will return http status code 200 if node running as replica. And final missing bit is a automation of generation of haproxy.cfg - it could be done with confd: https://github.com/kelseyhightower/confd https://github.com/kelseyhightower/confd And here is an example of template file: https://github.com/zalando/patroni/blob/master/extras/confd/templates/haproxy.tmpl https://github.com/zalando/patroni/blob/master/extras/confd/...
      - vishesh92 9y ago
        I am not sure, will HAProxy forcibly close connections to old master in case of a failover?
        CyberDem0n 9y ago
        on-marked-down shutdown-sessions should do the trick
      - deleted 9y ago
        [deleted]
jsiepkes 9y ago
Patroni makes PostgreSQL cloud native; easily add and despose nodes in a self healing postgres cluster. Think of it as nosql style cluster management. PostgreSQL XL is more "classic" (non self healing) clustering.

How does this compare to other HA postgres products like stolon or Postgres-XL?

by eicnix 9y ago

How does this compare to other HA postgres products like stolon or Postgres-XL?

As per my understanding, Postgres-XL is not comparable to Patroni. Postgres-XL is comparable to PostgreSQL. Postgres-XL shards the data across multiple data nodes. Where as Patroni uses etcd, consul or zookeeper to provide HA for any Postgres cluster using replication (Data is written only to a single instance and replicated further). I think you meant Stolon. Stolon is quite comparable to Patroni and has more features than Patroni, but I am not sure how many people are using it. I found more resources for Patroni as compared to stolon.

CyberDem0n 9y ago
> Stolon is quite comparable to Patroni and has more features than Patron. Let me as a question, what feature Stolon has and Patroni doesn't? Can you give an example? From my side I can provide list of features available in Patroni, but not in Stolon. For example: * there is no way to do a controlled failover (switchover) in Stolon. * in Patroni it's possible to exclude some nodes from a leader race. * Patroni supports cascading replication * Patroni can take basebackup from replicas if they are marked with a special tag * it's even possible to configure Patroni to use a custom backup/recovery solution instead of pg_basebackup * Patroni can give you a hint that postgres must be restarted to apply some configuration changes * with Patroni it's even possible to schedule switchover or restart restart of postges on some specific time (for example 04:00 am, when traffic is minimal) * with Patroni you can control High-Availability / Durability ratio. I.e.: what to do if master postgres has crashed? Either you will try to start it back or failover to a replica. But start of a crashed postgres may take a long time. With Patroni you can configure that if postgres didn't started in some amount of seconds - please do failover. Stolon provides cloud-native deployment and Patroni doesn't? This is not really true. The main idea of Patroni is to be not dependent on some specific technologies. It can work as on bare-metal with the same success as on Kubernetes. It's very easy to build a custom solution with Patroni for your use-case. For example there is a Spilo project: https://github.com/zalando/spilo https://github.com/zalando/spilo, a docker image build with Patroni and wal-e for a cloud deployments.
- vishesh92 9y ago
  Thanks for this. As I mentioned in previous comment, I couldn't find much about Stolon. One of things I likee in stolon is the proxy, it enforce connections to the right PostgreSQL master and forcibly closes connections to unelected masters. Which is not present in Patroni, but I guess it should be doable using consul's service discovery and dynamic DNS. (I am not sure if this can be done using etcd and zookeper).
  - CyberDem0n 9y ago
    Doesn't HAProxy provide such functionality? Patroni has REST API which can be used by HAProxy for a health-check. patroni:8008/master will return http status code 200 only if the node running as elected master patroni:8008/replica will return http status code 200 if node running as replica. And final missing bit is a automation of generation of haproxy.cfg - it could be done with confd: https://github.com/kelseyhightower/confd https://github.com/kelseyhightower/confd And here is an example of template file: https://github.com/zalando/patroni/blob/master/extras/confd/templates/haproxy.tmpl https://github.com/zalando/patroni/blob/master/extras/confd/...
    - vishesh92 9y ago
      I am not sure, will HAProxy forcibly close connections to old master in case of a failover?
      - CyberDem0n 9y ago
        on-marked-down shutdown-sessions should do the trick
    - deleted 9y ago
      [deleted]

jsiepkes 9y ago

Patroni makes PostgreSQL cloud native; easily add and despose nodes in a self healing postgres cluster. Think of it as nosql style cluster management. PostgreSQL XL is more "classic" (non self healing) clustering.