PowerFlex: key based SSH authentication fails with 'invalid privatekey'

PowerFlex deployment using Gateway will fails with the below error on the Gateway.

** scaleio-trace.log **

INFO  c.e.s.s.i.s.i.c.SSHNodeConnection - Connecting to LinuxSystemNode[nodeName=<null>,nodeIPs=[172.1.1.1],credentials=NodeCredentials[domain=<null>,userName=root]]
WARN  c.e.s.s.i.s.i.c.SSHNodeConnection - No credentials for SSH connection to node LinuxSystemNode[nodeName=<null>,nodeIPs=[172.1.1.1],credentials=NodeCredentials[domain=<null>,userName=root]], attempting keypass
INFO  ssh.SSHClient - Creating SSHClient with keys for 172.1.1.1
INFO  c.e.s.s.d.i.c.ValidateNodeCommand - running pre-executor for .ValidateNodeCommand
INFO  c.e.s.s.d.i.c.ValidateNodeCommand - running pre-executor for .ValidateNodeCommand complete in 0 ms
WARN  c.e.s.s.i.s.i.c.SSHNodeConnection - SSHNodeConnection: Failed to root@172.1.1.1. Reason: invalid privatekey: [B@3a7c1234
ERROR c.e.s.s.i.s.i.c.SSHNodeConnection - No password in the credentials for node LinuxSystemNode[nodeName=<null>,nodeIPs=[172.1.1.1],credentials=NodeCredentials[domain=<null>,userName=root]], SSH key failed as well.
INFO  c.e.s.s.i.s.i.NodeConnectionFactoryImpl - for node LinuxSystemNode[nodeName=<null>,nodeIPs=[172.19.244.71],credentials=NodeCredentials[domain=<null>,userName=root]] we should create new connection
ERROR c.e.s.scaleio.lockbox.LockBoxService - Trying to use LockBox, but it doesn't exist yet.
ERROR c.e.s.s.d.i.c.ValidateNodeCommand - Error The SSH key authentication failed on node 172.1.1.1, verify it matches the key on the gateway executing command .ValidateNodeCommand (retry): com.emc.s3g.scaleio.im.services.installation.connectors.SSHNodeConnection.connect(SSHNodeConnection.java:382)

Ensure that the private key is in PEM format.
For example:

# file /root/.ssh/id_rsa
/root/.ssh/id_rsa: PEM RSA private key



# cat /root/.ssh/id_rsa
-----BEGIN RSA PRIVATE KEY-----
-----END RSA PRIVATE KEY-----

In case if the file type is different, convert it to a PEM file or create the ssh Key using the command. 

ssh-keygen -m pem -t rsa