Python piramiko，建立SSH连接时连接超时错误

Question

I am working on a project in Python that will create an Amazon ec2 instance , and establish a SSH and SFTP connection to transfer files and commands between my machine and ec2 instance.

So I began to code, I coded the function that creates an ec2 instance using boto3 library.

# creating a file named sefa.pem that will store the private key
outfile = open('sefa.pem', 'w')
keypair = ec2.meta.client.create_key_pair(KeyName='sefakeypair')  # creates key pair
keyout= str(keypair['KeyMaterial'])  # reads the key material
outfile.write(keyout)  # writes the key material in sefa.pem

# creates the instance finally
response = ec2.create_instances(ImageId='ami-34913254', MinCount=1, MaxCount=1, InstanceType='t2.micro')

After that, I should establish a SSH Connection between my machine and ec2 instance to send command and I also should transfer and bring back files between my machine and ec2 instance.

After research, I found out that there is a Python library called piramiko for establishing SSH Connection and SFTP Connection between my computer and ec2 instance.

I tried to establish a SSH Connection between my computer and ec2 instance, but I have been facing with the "[Errrno 110]Connection Timed Out Error" for a day. I have been searching the internet for hours, but I couldn't find anything useful. Here is the code that emerges "Connection Time Out Error":

    con = paramiko.SSHClient()  # ssh client using paramiko library
    con.set_missing_host_key_policy(paramiko.AutoAddPolicy())  # this is needed because of adding policy automautically
    k = paramiko.RSAKey.from_private_key_file("sefa.pem")  # k reads sefa.pem and stores private key
    time.sleep(30)  # added this because ec2 should do 2/2 checks  before connecting
    print("connecting")
    con.connect(hostname=PUB_DNS, username="ubuntu", pkey=k, look_for_keys=True)  # HERE IS THE ERROR, I CAN'T CONNECT
    print("connected")
    stdin, stdout, stderr = con.exec_command('echo "TEST"')
    print(stdout.readlines())
    con.close()

I can not go any further without establishing a connection between my machine and ec2 instance.

• Do you have any suggestions to solve this problem?
• Is there any alternative library to piramiko?

Answer 1

I managed to solve the problem. The problem is my ec2 instance. These solved the issue:

• Make sure that instance's security group has ssh deamon and allows you to connect.
• Make sure that you have the keypair that you created while creating the instance.
• Make sure that you execute chmod 400 keypair.pem