Flask Traditional Deployments: Zero to One

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

Author: v1siuol

Last-Modified: 2018.08.13

Background

• A quite developed web project ( As a matter of fact, you don't have to prepare any codes, but deploying some simple easy sites costs a lot. For Flask case, flask run listens 127.0.0.1:5000 by default. However, flask run --host 0.0.0.0 listens a.b.c.d:5000 under the same wifi. Have fun with it first, then come and playing with VPS! )
• This series is a supplyment for Tradition Deploments in Chapter 17. Deployment in Flask Web Development, 2nd Edition written by Miguel Grinberg.
• Project address: https://github.com/v1siuol/v1siuol-site
• $ something refers to command line in bash

0. How to Select a Virtual Private Server

地区	服务	备注
国内	阿里云	需备案
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 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 in the same time continuouly for half 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:

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 permssions of your private key file as readonly.

   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 terminal for like 5 minutes.

   packet_write_wait: Connection to port 22: Broken pipe

   So I update the my connect by sending the 'HeartBeat‘ to server to hold my connection.

3. How to Close my VPC Connection

$ logout : then you will see Connection to 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.

Reference:

项目地址：https://github.com/v1siuol/v1siuol-site

网站地址：http://www.v1siuol.com/