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I'm trying to create an instance and login to the server using ssh, I'm following an example from a book:

import os
import time
import boto
import boto.manage.cmdshell

def launch_instance(ami="ami-54cf5c3d",
                    instance_type="t1.micro",
                    key_name="paws",
                    key_extension=".pem",
                    key_dir="~/.ssh",
                    group_name="paws",
                    ssh_port="22",
                    cidr="0.0.0.0/0",
                    tag="paws",
                    user_data=None,
                    cmd_shell=True,
                    login_user="ec2-user",
                    ssh_passwd=None):

    cmd=None
    ec2 = boto.connect_ec2() # Crededentials are stored in /etc/boto.cfg

    try:
        ec2.get_all_key_pairs(keynames=[key_name])[0]
    except ec2.ResponseError, e:
        if e.code == 'InvalidKeyPair.NotFound':
            print 'Creating keypair %s' % key_name
            key = ec2.create_key_pair(key_name)
            key.save(key_dir)
        else:
            raise

    try:
        group = ec2.get_all_security_groups(groupnames=[group_name])[0]
    except ec2.ResponseError, e:
        if e.code == 'InvalidGroup.NotFound':
            print 'Creating security group %s' % group_name
            group = ec2.create_security_group(group_name,
                                              'A group that allows SSH access')
        else:
            raise

    try:
        group.authorize('tcp',ssh_port,ssh_port,cidr)
    except ec2.ResponseError, e:
        if e.code == 'InvalidPermission.Duplicate':
            print 'Security group %s already authorized' % group_name
        else:
            raise

    reservation = ec2.run_instances(ami,
                                    key_name=key_name,
                                    security_groups=[group_name],
                                    instance_type=instance_type,
                                    user_data=user_data)
    instance = reservation.instances[0]

    print 'waiting for instance...'
    while instance.state != 'running':
        time.sleep(5)
        instance.update()
    print 'Instance is now running' 
    print 'Instance IP is %s' % instance.ip_address

    instance.add_tag(tag)

    if cmd_shell:
        key_path = os.path.join(os.path.expanduser(key_dir),
                                key_name + key_extension)
        cmd = boto.manage.cmdshell.sshclient_from_instance(instance,
                                                           key_path,
                                                           user_name=login_user)

    return (instance, cmd)


launch_instance()

and that's the output I'm getting:

root@johntheripper-PORTEGE-Z835:~/boto# python ec2_launch_test.py 
Security group paws already authorized
waiting for instance...
Instance is now running
SSH Connection refused, will retry in 5 seconds
SSH Connection refused, will retry in 5 seconds
SSH Connection refused, will retry in 5 seconds
SSH Connection refused, will retry in 5 seconds
SSH Connection refused, will retry in 5 seconds
Could not establish SSH connection

As you can see from the last line, that something wrong, I was thinking about permission, but even if I run it as a root, nothing changes.

However I'm able to connect to this instance through ssh -i ........ ec2-user@..... Can you please point me what I'm doing wrong?

4

2 回答 2

3

I think a better solution is to actually poll the instance to check if the ssh server is ready, then continue.

def poll_ssh(reservation): 
    # check if it is ready for ssh
    print '\nConnecting to ssh'
    for instance in reservation.instances:
        retry = True
        while retry:
            try:
                key_path = os.path.join(os.path.expanduser(KEY_DIR), KEY_NAME)
                key_path += '.pem'
                cmd = boto.manage.cmdshell.sshclient_from_instance(instance, key_path, user_name='ubuntu')
                #print 'debug: %s' % cmd
                if cmd:
                    retry = False #breaks the while loop once cmdshell returns true
                    cmd = None
                    print 'Connected to', instance
            except:
                time.sleep(5) # Let the sshd start up
        print 'Done\n'
于 2014-01-03T16:46:56.707 回答
2

Sometimes it takes awhile for the ssh server to start up even though the instance is "running".

Throw in a time.sleep(30) and then try to connect using ssh and it should work.

Reference

于 2013-03-12T20:12:24.120 回答