SFTP: Setting up SFTP on Google Cloud Platform (GCP)

Creating a Virtual Machine Instance on Google Cloud Platform (GCP), adding users, and verifying SFTP connections through SSH or password access to the VM.

Table of Contents

· Set Up SFTP Server
· Login the VM Instance Remotely
  ∘ Username and SSH key
  ∘ Username and Password

Set Up SFTP Server

1. Create a VM instance

GCP Compute Engine > VM Instance > CREATE INSTANCE

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2. Set up instance name, region, zone and machine type(CentOS)

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3. SSH into the VM instance

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Login the VM Instance Remotely

<claire@sftp-server ~>: terminal on vm instance

<claire@local>: terminal on local workstation

Username and SSH key

1. Create a new user

<claire@sftp-server ~> sudo adduser <USERNAME>

example:
<claire@sftp-server ~> sudo adduser test

2. Add ssh keys to instance metadata

• create and open a new text file on your workstation

<claire@local> touch <KEY_FILE>

example: 
<claire@local> touch sftp-server.txt

• save key in following format

<USERNAME>:<KEY_VALUE>

KEY_VALUE: content in ~/.ssh/<USERNAME>.pub

• add the ssh key to instance metadata

<claire@local> gcloud compute instances add-metadata <VM_NAME> 
               --metadata-from-file ssh-keys=<KEY_FILE>

example: 
<claire@local> gcloud compute instances add-metadata sftp-server 
               --metadata-from-file ssh-keys=sftp-server.txt

3. Access the sftp server from your terminal

<claire@local> sftp -i <PUBLIC_KEY> <USERNAME>@<VM_EXTERNAL_IP>

example:
<claire@local> sftp -i ~/.ssh/test.pub test@<VM_EXTERNAL_IP>

PUBLIC_KEY: ~/.ssh/<USERNAME>.pub

4. Confirm a successful SFTP server connection with the sftp> prompt in your terminal.

sftp>

Username and Password

1. Create a new user and password

<claire@sftp-server ~> sudo adduser <USERNAME>
<claire@sftp-server ~> sudo passwd <USERNAME>

eneter and verify the password

2. Enable password authentication

Edit sshd_config file.

<claire@sftp-server ~> sudo vi /etc/ssh/sshd_config

Uncomment PasswordAuthentication yes and comment out PasswordAuthentication no.

original:
# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
#PermitEmptyPasswords no
PasswordAuthentication no

after:
# To disable tunneled clear text passwords, change to no here!
PasswordAuthentication yes
#PermitEmptyPasswords no
#PasswordAuthentication no

3. Restart SSH service

<claire@sftp-server ~> sudo systemctl restart sshd

4. Connect to the sftp server from your terminal

<claire@local> sftp <USERNAME>@<VM_EXTERNAL_IP>

enter password

5. Confirm a successful SFTP server connection with the sftp> prompt in your terminal.

sftp>

Reference:

• Add SSH keys to VMs