Thanks for response.
Actually, I found many problem with sshing the instances even whiile proceeding by creating the ssh key first with nova keypair-add command line and then boot new instance by specifying the keyname but once ssh the instance it still not accpeted . I was following documentation in OpenStack website and get in -verbose mode such output:
ssh -vvvvvvvvvvvvv -i mykey root@10.10.10.1
OpenSSH_5.9p1 Debian-5ubuntu1, OpenSSL 1.0.1 14 Mar 2012
Warning: Identity file mykey not accessible: No such file or directory.
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 10.10.10.1 [10.10.10.1] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug3: Incorrect RSA1 identifier
debug3: Could not load "/root/.ssh/id_rsa" as a RSA1 public key
debug1: identity file /root/.ssh/id_rsa type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: identity file /root/.ssh/id_ecdsa type -1
debug1: identity file /root/.ssh/id_ecdsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.9p1 Debian-5ubuntu1
debug1: match: OpenSSH_5.9p1 Debian-5ubuntu1 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.9p1 Debian-5ubuntu1
debug2: fd 3 setting O_NONBLOCK
debug3: load_hostkeys: loading entries for host "10.10.10.1" from file "/root/.ssh/known_hosts"
debug3: load_hostkeys: found key type ECDSA in file /root/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys
debug3: order_hostkeyalgs: prefer hostkeyalgs: ecdsa-sha2-nistp256-cert-v01@openssh....
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ecdsa-sha2-nistp256-cert-v01@openssh....
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcf...
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcf...
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.co...
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.co...
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcf...
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcf...
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.co...
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.co...
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_setup: found hmac-md5
debug1: kex: server->client aes128-ctr hmac-md5 none
debug2: mac_setup: found hmac-md5
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: sending SSH2_MSG_KEX_ECDH_INIT
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ECDSA c6:8c:20:18:6d:e3:23:30:1f:25:0b:d4:10:31:0c:f2
debug3: load_hostkeys: loading entries for host "172.16.0.14" from file "/root/.ssh/known_hosts"
debug3: load_hostkeys: found key type ECDSA in file /root/.ssh/known_hosts:1
debug3: load_hostkeys ... (more)