使用ssh访问实例时报错"Permission denied(publickey)"

【以下的问题经过翻译处理】 如何通过ssh连接到AWS实例？

我已经完成以下操作：

注册了AWS账户；

在AWS网站上创建了一个公钥和证书，并将其保存到本地磁盘上；

进入控制台并创建了环境变量：

$ export JAVA_HOME=/usr/lib/jvm/java-6-openjdk/

$ export EC2_CERT=/home/default/aws/cert-EBAINCRNWHDSCWWIHSOKON2YWGJZ5LSQ.pem

$ export EC2_PRIVATE_KEY=/home/default/aws/pk-EBAINCRNWHDSCWWIHSOKON2YWGJZ5LSQ.pem

告诉AWS API使用此密钥对，并将密钥对保存到文件中：

$ ec2-add-keypair ec2-keypair > ec2-keypair.pem

使用此密钥对启动了一个AWS Ubuntu 9实例：

$ ec2-run-instances ami-ed46a784 -k ec2-keypair

尝试建立到实例的SSH连接：

$ ssh -v -i ec2-keypair.pem ubuntu@ec2-174-129-185-190.compute-1.amazonaws.com

OpenSSH_5.1p1 Debian-5ubuntu1, OpenSSL 0.9.8g 19 Oct 2007 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug1: Connecting to ec2-174-129-185-190.compute-1.amazonaws.com [174.129.185.190] port 22. debug1: Connection established. debug1: identity file ec2-keypair.pem type -1 debug1: Remote protocol version 2.0, remote software version OpenSSH_5.1p1 Debian-5ubuntu1 debug1: match: OpenSSH_5.1p1 Debian-5ubuntu1 pat OpenSSH* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_5.1p1 Debian-5ubuntu1 debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug1: kex: server->client aes128-cbc hmac-md5 none debug1: kex: client->server aes128-cbc hmac-md5 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug1: Host 'ec2-174-129-185-190.compute-1.amazonaws.com' is known and matches the RSA host key. debug1: Found key in /home/default/.ssh/known_hosts:11 debug1: ssh_rsa_verify: signature correct debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug1: SSH2_MSG_NEWKEYS received debug1: SSH2_MSG_SERVICE_REQUEST sent debug1: SSH2_MSG_SERVICE_ACCEPT received debug1: Authentications that can continue: publickey debug1: Next authentication method: publickey debug1: Trying private key: ec2-keypair.pem debug1: read PEM private key done: type RSA debug1: Authentications that can continue: publickey debug1: No more authentication methods to try. Permission denied (publickey).