Flask Traditional Deployments: Zero to One <Setup a VPS>

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The following article will introduce how to set up a virtual private server, and some basic Linux commands.

Background

  • A quite developed web project ( For Flask case, flask run listens 127.0.0.1:5000 by default, or flask run --host 0.0.0.0 to listen all public IPs, like a.b.c.d:5000. Have fun with this first, then come and play with VPS! )
  • This series is a supplement for Tradition Deployments in Chapter 17. Deployment in Flask Web Development, 2nd Edition written by Miguel Grinberg.
  • $ something refers to commands in bash

0. How to Select a Virtual Private Server

地区 服务 备注
国内 腾讯云 需备案
海外 AWS 国内的 AWS 由北京的光环新网运营

以上是些主流的云服务器啦，贵贵的。

I select AWS here since AWS provides a free tier for one year. For details, refer to https://aws.amazon.com/free/.

AWS Free Tier includes 750 hours of Amazon Elastic Compute Cloud (EC2) Linux t2.micro instance usage (1 GiB of memory and 32-bit and 64-bit platform support). Saying we can run 1 instance continuously for one month, or 2 instances at the same time continuously for half a month.

It also includes 30 GB of Amazon Elastic Block Storage (EBS) in any combination of General Purpose (SSD) or Magnetic, plus 2 million I/Os (with EBS Magnetic) and 1 GB of snapshot storage.

1. How to Create the Amazon EC2

Official documents: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/get-set-up-for-amazon-ec2.html

Basic steps:

  1. Sign Up for AWS
  2. Create an IAM User
  3. Create a Key Pair
  4. Create a Virtual Private Cloud (VPC)
  5. Create a Security Group

My VPC is like this:

  1. AMI: Ubuntu Server 16.04 LTS (HVM), SSD Volume Type - ami-5e8bb23b

    Ubuntu Server 16.04 LTS (HVM), EBS General Purpose (SSD) Volume Type.

  2. Instance type: t2.micro (Variable ECUs, 1 vCPUs, 2.5 GHz, Intel Xeon Family, 1 GiB memory, EBS only)

2. How to Connect to my VPC

Official documents: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AccessingInstancesLinux.html

Two commands using in my Mac terminal:

  1. $ chmod 400 /path/my-key-pair.pem

    This is used to set the permissions of your private key file as read-only.

    The link to learn more on chmod : https://chmodcommand.com/chmod-400/

  2. $ ssh -i /path/my-key-pair.pem user_name@public_dns_name

    Default user_name is like:

    • For Amazon Linux 2 or the Amazon Linux AMI, the user name is ec2-user.
    • For a Centos AMI, the user name is centos.
    • For a Debian AMI, the user name is admin or root.
    • For a Fedora AMI, the user name is ec2-user or fedora.
    • For a RHEL AMI, the user name is ec2-user or root.
    • For a SUSE AMI, the user name is ec2-user or root.
    • For an Ubuntu AMI, the user name is ubuntu.
    • Otherwise, if ec2-user and root don’t work, check with the AMI provider.

    public_dns_name is like:ec2-198-51-100-1.compute-1.amazonaws.com

  3. The updated version of my second command: $ ssh -o TCPKeepAlive=yes -o ServerAliveInterval=60 -i /path/my-key-pair.pem user_name@public_dns_name

    In my practice, I usually encounter if I do nothing in the terminal for like 5 minutes.

    packet_write_wait: Connection to <ip> port 22: Broken pipe

    So I update the connection by sending the “HeartBeat” to the server to hold my connection.

3. How to Close my VPC Connection

$ logout : then you will see Connection to <public_dns_name> closed. .

4. (Optional) How to transfer files between my PC and EC2

  1. Send files from PC to EC2: PC --> EC2

    $ scp -i /path/my-key-pair.pem /path/SampleFile.txt user_name@public_dns_name:/path

    /path : my suggestion is to use ~ or /tmp . If sending to other paths in your EC2, it might say permission denied .

    So after scp the file to /tmp , ssh to your server and use command mv /tmp/SamepleFile.txt /path/you_want .

  2. Send files from EC2 to PC: EC2 --> PC

    $ scp -i /path/my-key-pair.pem user_name@public_dns_name:/path_in_EC2/SampleFile.txt ~/path_on_PC

Thank you.

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