python：如何从EC2实例在本地计算机上运行命令

Question

I am trying to automate the process of creating a postgres database from production dump using a python script. I am running this script on an EC2 instance that hosts an RoR app server.

I am able to create the DB using psychopg. But in the same script I want to do the following:

- do a deploy using capistrano from local machine

I came across paramiko - SSHClient in my research. I think it can be used. But I'm not sure how I can SSH from an EC2 instance to my local machine. I found out my IP(say abcd) and tried ssh abcd from the EC2 instance but it says:

ssh: connect to host a.b.c.d port 22: Connection refused

So my question is: - If this method (using paramiko) is correct, how can I set up a ssh connection from EC2 instance to my local machine OR If paramiko cannot achieve this, how can I run the deploy from my script that is on the EC2 instance

Answer 1

For one, paramiko is a bit low-level, you could try using Fabric , it will make a lot of things much easier.

Secondly, check whether your local machine is

• accessible from the internet, ie has public IP address
• running SSH (assuming you run *NIX-like OS, run ps -ef | grep sshd , if you see a process matching, then you should be able to connect)

Then, if you wanna automate a postgres DB creation on a EC2 instance, why do you need a connection from it to your local machine. Wouldn't it be more logical to reverse the process? Ie SSH from local machine to EC2 instance.