Getting and Checking RDS/Aurora Log Files with AWS CLI

This is intended for use when checking from the CLI is more convenient than using the Management Console.

Pre-requisites

Install jq for formatting output:

sudo yum -y install jq

How to Get Log Files

aws rds describe-db-instances | jq '.DBInstances[].DBInstanceIdentifier'
aws rds describe-db-log-files --db-instance-identifier aurorapostgresqlv1-instance-1
aws rds download-db-log-file-portion --db-instance-identifier aurorapostgresqlv1-instance-1 --log-file-name "error/postgres.log" --output text

Execution Examples

Get the Target Instance Name

[ec2-user@bastin ~]$ aws rds describe-db-instances | jq '.DBInstances[].DBInstanceIdentifier'
"aurorapostgresqlv1-instance-1"
[ec2-user@bastin ~]$

Get the Available Log Files

Whether it is the latest file can be verified from LastWritten.

[ec2-user@bastin ~]$ aws rds describe-db-log-files --db-instance-identifier aurorapostgresqlv1-instance-1
{
    "DescribeDBLogFiles": [
        {
            "LastWritten": 1582951862000,
            "LogFileName": "error/postgres.log",
            "Size": 1380
        },
        {
            "LastWritten": 1582951868000,
            "LogFileName": "error/postgresql.log.2020-02-29-0451",
            "Size": 891
        },
        {
            "LastWritten": 1582952400000,
            "LogFileName": "error/postgresql.log.2020-02-29-0500",
            "Size": 0
        },
        {
            "LastWritten": 1582956000000,
            "LogFileName": "error/postgresql.log.2020-02-29-0600",
            "Size": 0
        }
    ]
}

Output the Log File

[ec2-user@bastin ~]$ aws rds download-db-log-file-portion --db-instance-identifier aurorapostgresqlv1-instance-1 --log-file-name "error/postgres.log" --output text
2020-02-29 04:51:01.093 GMT [5665] LOG:  skipping missing configuration file "/rdsdbdata/db/postgresql.auto.conf"
2020-02-29 04:51:01 UTC::@:[5665]:WARNING:  unrecognized configuration parameter "rds.custom_dns_resolution"
2020-02-29 04:51:01 UTC::@:[5665]:WARNING:  unrecognized configuration parameter "rds.enable_plan_management"
2020-02-29 04:51:01 UTC::@:[5665]:LOG:  database system is shut down
Postgres Shared Memory Value: 11132993536 bytes
2020-02-29 04:51:02.647 GMT [5783] LOG:  skipping missing configuration file "/rdsdbdata/db/postgresql.auto.conf"
2020-02-29 04:51:02 UTC::@:[5783]:WARNING:  unrecognized configuration parameter "rds.custom_dns_resolution"
2020-02-29 04:51:02 UTC::@:[5783]:WARNING:  unrecognized configuration parameter "rds.enable_plan_management"
2020-02-29 04:51:02 UTC::@:[5783]:LOG:  listening on IPv4 address "0.0.0.0", port 5432
2020-02-29 04:51:02 UTC::@:[5783]:LOG:  listening on IPv6 address "::", port 5432
2020-02-29 04:51:02 UTC::@:[5783]:LOG:  listening on Unix socket "/tmp/.s.PGSQL.5432"
2020-02-29 04:51:02 UTC::@:[5783]:LOG:  could not write pg_stat_statement file "pg_stat_tmp/pgss_query_texts.stat": No such file or directory
2020-02-29 04:51:02 UTC::@:[5783]:LOG:  redirecting log output to logging collector process
2020-02-29 04:51:02 UTC::@:[5783]:HINT:  Future log output will appear in directory "/rdsdbdata/log/error".