Problem connecting to RDS from EC2 instance: Is the server running on host/accepting TCP/IP connections on port 5432?

Question

I have personal AWS EC2 server and I'm using ssh into this server. I installed PostgreSQL on the EC2 instance, cerated a PostgreSQL RDS, and trying to connect to the RDS from EC2 CLI. I get following error:

Is the server running on host "db-xxxx.us-east-2.rds.amazonaws.com" and accepting TCP/IP connections on port 5432?

I have: - change RDS to publicly accessible - added listen_addresses = '*' to postgres.conf - added 0.0.0.0/0 md5 to pg_hba.conf

  # IPv4 local connections:
  host    all             all             0.0.0.0/0            md5

• ensured both EC2 and RDS have same security group
• added security-group-for-inbound-nfs-xx to RDS

• enabled IAM authorization on RDS

  output of "service postgresql status" shows postgres is running and listening on the port 5432

Redirecting to /bin/systemctl status postgresql.service ● postgresql.service - PostgreSQL database server Loaded: loaded (/usr/lib/systemd/system/postgresql.service; enabled; vendor preset: disabled) Active: active (running) since Wed 2020-06-03 04:28:54 UTC; 20min ago Process: 3065 ExecStartPre=/usr/libexec/postgresql-check-db-dir %N (code=exited, status=0/SUCCESS) Main PID: 3070 (postmaster) CGroup: /system.slice/postgresql.service ├─3070 /usr/bin/postmaster -D /var/lib/pgsql/data ├─3084 postgres: logger process
├─3089 postgres: checkpointer process
├─3090 postgres: writer process
├─3091 postgres: wal writer process
├─3092 postgres: autovacuum launcher process
├─3093 postgres: stats collector process
└─3094 postgres: bgworker: logical replication launcher

I see postgres is running and listning on the port 5432.

postmaster[3070]: 2020-06-03 04:28:54.168 UTC [3070] LOG: listening on IPv4 address "0.0.0.0", port 5432 Jun 03 04:28:54 ip-172-xx-xx-xx9.us-east-2.compute.internal postmaster[3070]: 2020-06-03 04:28:54.168 UTC [3070] LOG: listening on IPv6 address "::", port 5432 Jun 03 04:28:54 ip-172-xx-xx-xx9.us-east-2.compute.internal postmaster[3070]: 2020-06-03 04:28:54.169 UTC [3070] LOG: listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432" Jun 03 04:28:54 ip-172-xx-xx-xx.us-east-2.compute.internal postmaster[3070]: 2020-06-03 04:28:54.171 UTC [3070] LOG: listening on Unix socket "/tmp/.s.PGSQL.5432" Jun 03 04:28:54 ip-xx-xx-xx.us-east-2.compute.internal postmaster[3070]: 2020-06-03 04:28:54.198 UTC [3070] LOG: redirecting log output to logging collector process Jun 03 04:28:54 ip-xx-xx-xx.us-east-2.compute.internal postmaster[3070]: 2020-06-03 04:28:54.198 UTC [3070] HINT: Future log output will appear in directory "log". Jun 03 04:28:54 ip-172-31-36-109.us-east-2.compute.internal systemd[1]: Started PostgreSQL database server.

I have verified everything provided here:

https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ConnectToPostgreSQLInstance.html

https://aws.amazon.com/premiumsupport/knowledge-center/rds-connectivity-instance-subnet-vpc/

What am I missing? Thanks for the help.

Answer 1

Well, RDS will tell you the endpoint of your PSQL, and the default port would be 5432 right. But I suggest you do the double-check if the endpoint you connected is the same with the RDS dashboard.

https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ConnectToPostgreSQLInstance.html