Although passwordless ssh connection is established between compute node and cell nodes in the Exadata installation, this connection can be broken due to some problems. When patching Infiniband switches, passwordless ssh connection must be possible.
We can do these operations with dcli.
First, a file must be created that contains the server or switches to which the passwordless ssh connection will be made. For example, a file with the name all_group can be created as follows. Server names in the file should be in short format and these names should be solved by DNS.
Create SSH Authentication Keys
The following command is then run with the user you want to connect to to create SSH authentication keys.
# ssh-keygen -t rsa
These keys are then distributed to all servers in the file we created with the name all_group. When the command is executed it will ask for the passwords of the servers.
# dcli -g ./all_group -l root -k -s '-o StrictHostKeyChecking=no'
Check Passwordless Connection
Finally check the passwordless connection. The date on the servers can be queried using the following command. If dates are displayed on all servers, we can say that there is no problem with the passwordless ssh connection.
# dcli -g all_group -l root date