Master server : A postgresql user by name 'test' is there with password 'mytest-password-formaster'
Slave server : A postgresql user by name 'test' is there with password 'mytest-password-forslave'
Now, i have created HA setup as follows:
Modified postgresql.conf and pg_hba.conf on master required to act as 'master'
on slave server: Cleaned up data_dir, modified postgresql.conf, took data_dir backup from master using "pg_basebackup", and created reconvery.conf to start the postgresql in hotstandby mode.
Now, above steps works fine and my HA setup is also working. Now when i promote the slave server using 'pg_promote', it makes postgresql write enabled. Now the password for 'test' user is of master. i.e 'mytest-password-formaster'.
what i want is, when i promote standby node using 'pg_promote', it should have old password for its user i.e 'mytest-password-forslave'.
How to achieve this ? It is happening as i cleaned up data_dir on slave when setting standby configuration ?
Related
I've followed the instructions to set up a replica server of PostgreSQL with repmgr, But I can't start the PostgreSQL service because of a permission problem.
On the stand by server, I have this on my /etc/repmgr.conf file:
node_id=2
node_name=aws-replica
conninfo='host=<REDACTED> user=repmgr dbname=repmgr port=5432'
data_directory='/mnt/data/postgres/data'
log_file='/var/log/repmgr.log'
As you can see, I've changed the location of the data directory to /mnt/data/postgres/data and also updated the postgresql.conf file with the same information.
When I try to start the PostgreSQL service, I get this error on journalctl:
FATAL: data directory "/mnt/data/postgres/data" has wrong ownership
HINT: The server must be started by the user that owns the data directory.
The folder in question is owned by a normal user, the same one that runs repmgr. If I set the ownership of the folder to postgres:postgres, then repmgr can't perform any operations because it can't access the folder. I tried joining the postgres group, but the service won't start unless the folder has 700 permissions, so it's pointless to join the group.
So, I'm either not being able to start postgresql or repmgr. What can I do to make it work?
The problem was that I created a postgres DB using innitdb, which wasn't necessary. I deleted the database and then ran repmgr as the postgres user, and it worked.
I have a master\server setup with pgpool and postgres 9.5. Both servers are running on centOS7.
I wanted to setup a point in time recovery with base backups every saturday, eliminating the old xlogs.
The server is archiving the xlogs with success on a external filesystem.
But when I try to execute the basebackup command it gives the following error:
pg_basebackup: could not connect to server: FATAL: database "replication" does not exist.
You seems to be missing the explicit HBA record for replication database, because specifying all does not covers the replication connections
host replication postgres 127.0.0.1/0 trust
The value replication specifies that the record matches if a
replication connection is requested (note that replication connections
do not specify any particular database). Otherwise, this is the name
of a specific PostgreSQL database.
I have tried to do database replication in linux 7.0 red hat using postgresql.
I refered this URL for Confuring http://blog.terminal.com/postgresql-replication-and-backup-methods/ I completed the the steps upto this step
Configuring the slave server
but the step
Initial replication
when I executed this command in Master
-bash-4.2$ psql -c "select pg_start_backup('initial_backup');"
I got Error Like this
ERROR: WAL level not sufficient for making an online backup
HINT: wal_level must be set to "archive" or "hot_standby" at server start.
So kindly let me know where we are wrong.
On your master PostgreSQL server's configuration file <PG_DATA>/postgresql.conf there is parameter called wal_level it should be set to either "archive" or "hot_standby"
Both said to postgres to keep WAL segmetnts for replication server. The difference between the two is rather simple:
"hot_standby" means that your replication server will allow connections for SELECT statements
"archive" means you don't want that possibility.
More to read in this tutorial on streaming replication
Also keep in mind that change of wal_level property needs server restart to take an effect.
Today I set up pgpool-II on one of my company servers for database replication purposes and I'm trying to connect to it from my application located on another server. Previously it connected to database on the same server where pgpool is now installed without problems - I just needed to provide something like this link in config file:
database: postgresql://user:password#host:port/db_name
I have changed port to the one on which pgpool listens for connections and provided user and password from pcp.conf, but then I get a list of errors after starting app, all of them of the same type:
OperationalError: (OperationalError) unable to open database file None None
Doesn't matter if I'm authenticating as postgresql or pgpool user and if I provide md5 encrypted or plaintext password, errors are the same. How can I properly connect to my database then?
Problem solved days ago, needed to change administrative database in pgpool config from "template1" to "postgres". IDK why it doesn't default to that.
I have a server that I want to use for testing new app verson (say staging server), but at same time I want to use it as replication slave for MongoDB. So, there is two roles:
always replicate an database to this server (only one database, original, with real data)
after deployment, make a copy of original db, to a new one (*-staging db), and test my deployment against this database
I see from docs how to replicate only specified database from one server to another, seems that it's working fine. But the problem that when i've tried to make a copy of existing database, on slave server, it fails with error not master. I don't want to make this database copy on master server, because it means that all staging tests will be executed against master server, that doesn't work for me.
Does it mean that I can't have MongoDB master for one database, and slave for another?
Slaves by default are read only but you can achieve what you are trying to do by making it master and slave at the same time by passing both --master and --slave when starting your server:
mongod --slave --source master:1234 --master