Update README.md

Author: mohit4buntikki

common/db/README.md

@@ -1,17 +1,60 @@
-### Generating Key Pair for DB
+### STEP 1 Generating Key Pair for DB
 
-1. RUN `ssh-keygen -t rsa` to generate a key pair
-2. Set value of `cat ~/.ssh/id_rsa | base64 -w 0` in DB_SSH_PRIVATE_KEY (change the location of private key in command if needed)
-3. Set value of `cat ~/.ssh/id_rsa.pub | base64 -w 0` in DB_SSH_PUBLIC_KEY (change the location of private key in command if needed)
+A. RUN `ssh-keygen -t rsa` to generate a key pair
+B. Set value of `cat ~/.ssh/id_rsa | base64 -w 0` in DB_SSH_PRIVATE_KEY (change the location of private key in command if needed)
+C. Set value of `cat ~/.ssh/id_rsa.pub | base64 -w 0` in DB_SSH_PUBLIC_KEY (change the location of private key in command if needed)
 
-### Steps to follow after the db container is started (only if you have enabled barman)
+### Step 2 Follow after the db container is started (only if you have enabled barman)
 
-1. Currently the ssh server doesn't start automatically, run `docker exec -it DB_CONTAINER_ID /usr/sbin/sshd` to start the ssh server inside the db container
+A. Currently the ssh server doesn't start automatically, run `docker exec -it DB_CONTAINER_ID /usr/sbin/sshd` to start the ssh server inside the db container
+B. Create barman and streaming_barman user in postgres to setup barman disaster recovery later.
+   
+   `docker exec -it DB_CONTAINER_ID bash`
+   
+   `su - postgres`
+   
+   `createuser --superuser --replication -P barman` password you set will be needed to setup barman later.
+   
+   `createuser --replication -P streaming_barman` password you set will be needed to setup barman later
+   
+   Now exit from container using `exit` command twice.
+   
+C. Copy the public key of postgres user which is required to setup barman later, run `docker exec -it DB_CONTAINER_ID cat /var/lib/postgresql/.ssh/id_rsa.pub` to get the public key.
 
-### Steps to setup Barman 
+### Step 3  Follow to setup Barman.
+A. Switch to root user `sudo -i`
+B. Create a DNS entry in /etc/hosts file for postgres server.
 
-1. Run `make setup-barman` to setup barman 
+   `vi /etc/hosts` edit the file and add `POSTGRES_IP  mydb` replace POSTGRES_IP with actual IP address of postgres container/server and mydb with name you want to set this domain name is required while setting up barman.
+   
+C. Run `make setup-barman` in barman server to setup barman, provide the following value when asked :
+   ```
+- HOSTNAME/DOMAIN name of your server (e.g mydb.example.com , mydb) which you have set in previous step.
+- Database name for which backup needs to be created (e.g postgres or any database name).
+- Password of user 'barman' which was created while configuring barman user in STEP 2.B.
+- Password of user 'streaming_barman' which was created while configuring streaming_barman user in STEP 2.B.
+```
+
+D. Switch to barman user and generate the barman key pair.
+
+`su - barman`
+
+`ssh-keygen -t rsa`
+
+E. Add the postgres public key (refer to STEP 2.C) in .ssh/authorized_keys file located in barman's home directory.
+
+`vi ~/.ssh/authorized_keys` paste the public key of postgres user.
+
+F. Copy the public key of barman user and paste it in the postgres user's authorized_keys running in container
+
+`cat ~/.ssh/id_rsa.pub` copy the content 
+
+#### STEP 4 connect to postgres container and add public key of barman to postgres user's authorized key.
+
+`docker exec -it CONTAINER_ID bash`
+
+`su - postgres`
+
+`vi ~/.ssh/authorized_keys`
 
-> [!NOTE]
 
-> 1. We will require the public key generated here while we setup Barman