mysql-replica | MySQL replication master-slave example | Continuous Deployment library
kandi X-RAY | mysql-replica Summary
kandi X-RAY | mysql-replica Summary
One of the most common feature requested for the MySQL docker official image is adding replication master/slave ability. As docker-library/mysql#43 is closed by deciding that it's a feature should be implemented via init script, my example here is a demo of how to do it. The official MySQL image have the customize ability by running script files under /docker-entrypoint-initdb.d/ directory. The script has to be either a shell script, .sh, or a SQL script, .sql or .sql.gz. To implement the MySQL replication, I borrowed the code from PR: docker-library/mysql#43, modified and saved as replica.sh. As described in the script comments, we have 5 more special environment variables for replication. The Dockerfile is very simple, just copied replica.sh to /docker-entrypoint-initdb.d/ directory. That's it. The reason why I create a new Docker image here, instead of mount the file directly into container during the runtime, is that, it's not easy to maintain the updated file across the cluster. Put it into the Docker image is best way to handle such static config file in cluster environment.
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QUESTION
I want to set up a complete server (apache, mysql 5.7) as a fallback of a productive server. The synchronization on file level using rsync and cronjob is already done.
The mysql-replication is currently the problem. More precisely: the choice of the right replica method.
Multi primary group replication seemed to be the most suitable method so far. In case of a longer production downtime, it is possible to switch to the fallback server quickly via DNS change. Write accesses to the database are possible immediately without adjustments.
So far so good: But, if the fallback-server fails, it is in unreachable status and the production-server switches to read only, since its group no longer has the quota. This is of course a no-go. I thought it might be possible using different replica variables: If the fallback-server is in unreachable state for a certain time (~5 minutes), the production-server should stop the group_replication and start a new group_replication. This has to happen automatically to keep the read-only time relatively low. When the fallback-server is back online, it should be manually added to the newly started group. But if I read the various forum posts and documentation correctly, it's not possible that way. And running a Group_Replication with only two nodes is the wrong decision anyway.
https://forums.mysql.com/read.php?177,657333,657343#msg-657343
Is the master - slave replication the only one that can be considered for such a fallback system? https://dev.mysql.com/doc/refman/5.7/en/replication-solutions-switch.html
Or does the Group_Replication offer possibilities after all, if you can react suitably to the quota problem? Possibilities that I have overlooked so far.
Many thanks and best regards
...ANSWER
Answered 2022-Feb-23 at 19:50Short Answer: You must have [at least] 3 nodes.
Long Answer:
Split brain with only two nodes:
- Write only to the surviving node, but only if you can conclude that it is the only surviving node, else...
- The network died and both Primaries are accepting writes. This to them disagreeing with each other. You may have no clean way to repair the mess.
- Go into readonly mode with surviving node. (The only safe and sane approach.)
The problem is that the automated system cannot tell the difference between a dead Primary and a dead network.
So... You must have 3 nodes to safely avoid "split-brain" and have a good chance of an automated failover. This also implies that no two nodes should be in the same tornado path, flood range, volcano path, earthquake fault, etc.
You picked Group Replication (InnoDB Cluster). That is an excellent offering from MySQL. Galera with MariaDB is an equally good offering -- there are a lot of differences in the details, but it boils down to needing 3, preferably dispersed, nodes.
DNS changes take some time, due to the TTL. A proxy server may help with this.
Galera can run in a "Primary + Replicas" mode, but it also allows you to run with all nodes being read-write. This leads to a slightly different set of steps necessary for a client to take to stop writing to one node and start writing to another. There are "Proxys" to help with such.
FailBack
Are you trying to always use a certain Primary except when it is down? Or can you accept letting any node be the 'current' Primary?
I think of "fallback" as simply a "failover" that goes back to the original Primary. That implies a second outage (possibly briefer). However, I understand geographic considerations. You may want your main Primary to be 'near' most of your customers.
QUESTION
I'm looking for a way to fetch following information from SHOW SLAVE SATUS on MASTER server in MySQL 5.6:
Slave_IO_RunningSlave_SQL_RunningSeconds_Behind_Master
SHOW SLAVE SATUS shows me info only on replica/slave server, where read-only mode is my only possibility, which makes writing procedure unavailable for me.
I found this answers somewhat usefull, unfortunetly relates on querying slave server, which is not my target and are usefull mostly for MySQL above 5.6.
...ANSWER
Answered 2021-Jun-22 at 03:08slave keeps info by default in master info file. So you can fetch like this on bash
mysql -uUSER -pPASSWORD -e "show slave status\G" | egrep '(Seconds_Behind_Master|Slave_IO_Running|Slave_SQL_Running)'
QUESTION
- k8s cluster
- AKS
- version: 1.18.14
- StorageClass
- azure files dynamic
I made an effort to implement MySQL Replication in k8s by referring to the official documentation.
However, when I try to implement it in the same way as the official document, I get an error.
ErrorA Warning BackOff 3m32s (x26 over 8m27s) kubelet Back-off restarting failed container error occurred at index 0 mysql-0 pod of StatefulSet.
After confirming the error that occurred inside the container, the internal log is displayed as a result, as shown below.
...ANSWER
Answered 2021-Apr-07 at 09:21The error you encounter:
QUESTION
I am working on pushing my single mysql data to elasticsearch using fluentd mysql-replicator plugin , But my fluentd throw following error. There is no enough documentation available on internet So please help reg this error.
I am using td-agent v3 (fluentd 1.10.x) version on windows local machine with Elasticsearch version as 7.7.1. I am running this config file as C:\opt\td-agent>fluentd -c etc\td-agent\td-agent.conf from Td-agent Command Promt
...ANSWER
Answered 2020-Dec-07 at 15:08You should use the following tag_format:
QUESTION
I am install MySQL HA in kubernetes v1.16.0 cluster using helm:
...ANSWER
Answered 2020-Jun-08 at 07:29report-mysqlha-0 is the name of the pod and not the name of the service. Hence you can't access it via report-mysqlha-0.middleware.svc.cluster.local
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