Private PyPI Server

The Private PyPI Server creates a PyPI server for hosting your own Python Packages. The server can be password protected to host private Python packages.

The Python packages are stored on an EFS filesystem mount. The PyPI server is hosted in an AutoScalingGroup and will automatically relaunch and remount the EFS filesystem if the server is terminated. Configuration is included which can be enabled to do routine back-ups on the EFS filesystem and monitor the PyPI server and alert if the server is not responding.

The PyPI server can be run with two network configurations: “budget” and “professional”. The first configuration runs a simple single public network with the server directly serving requests to the internet with an ElasticIP.

The second configuration has public and private subnets with an an Application Load Balancer (ALB) in the public subnet and a NAT Gateway to allow the web server(s) internet access. This increases the overall cost of the solution but allows for more robust uptime and improved security. The Application Load Balancer is run in a separate application named “shared”. This configuration is designed to show you how a real-world AWS deployment might run a single ALB and direct requests to a variety of backend resources.

Create a “Private PyPI Server” Project

Install Paco and then get started by running the paco init project <your-project-name> command. Review the instructions on Getting Started with Paco to understand the importance of name fields in Paco and the difference between a name and title. Then follow the instructions on creating credentials for your project to connect it to your AWS Account.

When asked “Budget - Lower cost but less robust set-up?” if you choose “Y” your configuration will run a single server in a public subnet, if you choose “N” your configuration will have public/private subnets and an Application Load Balancer and NAT Gateway. The latter configuration increases your monthly costs by over $30 USD per month but allows you to run a fault tolerant cluster of servers.

Take a minute to set-up a PACO_HOME environment variable, this will save you lots of time typing.

Provision SNS Topics and EC2 Keypairs

If you want to configure monitoring and alerting to let you know when your PyPI server is having potential problems, you will need to provision SNS Topics. The “admin” group group is configured to recieve any alarm notifications. The project default is to use the same email as your root account, but you can edit resource/snstopics.yaml and change this to whatever you want. See the SNS Topics docs for examples.

paco provision resource.snstopics

Next, you will need to have an EC2 SSH Keypair in the same account and region as your PyPI deployment. You can create a new keypair by running:

paco provision resource.ec2.keypairs

Alternatively, you can edit resource/ec2.yaml and configure it to use an existing EC2 Keypair, if you already have one created. See the EC2 Key pairs reference documentation for more information.

Provision the PyPI server resources

Now you are ready to provision the PyPI server. This will provision everything you need - VPC network, EFS filesystem, AutoScalingGroup server(s). After this step, you should have a fully working PyPI server!

paco provision netenv.mynet.prod

If you changed your NetworkEnvironment name, change the mynet string to that name. This starter project only contains a single “prod” environment. However, Paco supports easily cloning environments, so you could provision a completely duplicate “dev” or “test” environment if you did need a place to test new changes to your PyPI set-up without impacting your production environment.

To visit your new PyPI server, if you are running the “budget” set-up, use the AWS Console to go to EC2 –> Instances and click on your server. Find the Elastic IPs field:

_images/pypi-eip.png

Copy that IP into your web browser and your server will be running on port 8080, for example: http://255.255.255.255:8080

The PyPI server runs as a www-data user for security reasons. This user doesn’t have permissions to bind to port 80, so port 8080 is used instead.

If you are running the non-budget configuration, then you can go to EC2 –> Load Balancers in the AWS Console and find the DNS name for your ALB. Put this name into your web browser and you should see your PyPI server:

_images/pypi-server.png

Using and managing your PyPI server

The PyPI server is running the pypiserver application. The default configuration runs the PyPI server as a private package server and requires authentication to download packages. It uses an htpasswd.txt file to contain the usernames and passwords for the server.

You can customize your PyPI server if you want to make it public or use a different authentication method. Visit the pypiserver GitHub page to see all of the option available for server configuration.

The PyPI server is started and configured automatically by SystemD when a new EC2 instance launches. The configuration management for the server is done with AWS CloudFormationInit. You will see a file in your Paco project at netenv/pypi-config/pypiserver.service which contains the PyPI server configuration. You can customize the configuration here, pay attention to the ExecStart= line which contains all of the configuration options supplied to the PyPI server.

Take note that your packages are served from the directory /var/pypi/. Paco has provided configuration to automatically mount this directory to an EFS filesystem mount. The default configuration will also have created a /var/pypi/htpasswd.txt file which contains a starting username and password of “uploader” and “Pass123…”. This is a public example password, you will want to change this file and replace it with private usernames and passwords!

You will have a file at netenv/pypi-config/htpasswd.txt which contains an Apache-style htpasswd file. You can run the htpasswd CLI to add new usernames to this file:

htpasswd -b ./netenv/pypi-config/htpasswd.txt newuser NewPassword123!

The contents of this file is embedded into the CloudFormation template used to provision the PyPI server AutoScalingGroup. You can add and remove passwords locally and then run:

paco provision -y netenv.mynet.prod

This will apply changes to the file to the CloudFormation stack. The PyPI server is configured to run cfn-hup to automatically ping the CloudFormation service every 15 minutes and if new changes are detected, to automatically apply them to the PyPI server.

This is a simple and easy way to manage PyPI server passwords, but it does expose hashed passwords in both your Paco project (which you will likely want to keep in a git repo) and through your AWS Console. These passwords could then be compromised through brute force. If you want to run stricter security on your PyPI authentication, then change the authentication configuration and you can disable cfn-hup in your netenv/mynet.yaml file:

cfn-hup:
  enabled: false
  ensure_running: false

Finally,

Paco project configuration

Paco project’s are designed to be easily configurable. Let’s look at some configuration changes you could make to your project.

SSH Access

With the SSH keypair that you used to launch your PyPI server, you can SSH to your server. You may find this necessary if you want to remove packages from your PyPI server, or if you are trying to change the pypiserver

ssh -i ~/.ssh/my-keypair.pem [email protected]<my-eip-address>

In the budget set-up, you can SSH directly to your server. You will see this configuration in your netenv/mynet.yaml file:

  • port: 22 name: SSH protocol: tcp cidr_ip: 0.0.0.0/0 # change to your IP to improve security

Change the open to the world “cidr_ip: 0.0.0.0/0” string to your IP address (e.g. “cidr_ip: 120.90.255.120/32”) and run paco provision netenv.mynet.prod to limit access to just your IP address.

With the ALB set-up, you will need to launch a bastion server to be able to SSH to your PyPI server. To enable the bastion you will need to enable it’s configuration in the environments.prod.applications section:

environments:
  prod:
    title: "Production Environment"
    ...
    applications:
      pypi:
        enabled: true
      bastion:
        enabled: true

And then run paco provision netenv.mynet.prod and the instance will be launched.

Application Load Balancer (ALB)

The non-budget set-up runs behind an Application Load Balancer (ALB). This ALB can be configured to serve requests for other applications. In addition, you can conifgure it to connect to your Route 53 hosted zone for your domain and serve traffic over HTTPS.

The default configuration listens on port 80 only, but you will see commented out configuration to instead listen on port 443. In your netenv/mynet.yaml find this configuration under the “listeners:” field:

http:
  port: 80
  protocol: HTTP
  target_group: pypi
  rules:
    pypi_forward:
      enabled: true
      rule_type: forward
      host: 'pypi.example.com'
      target_group: pypi
      priority: 10

Remove this configuration and uncomment everything below it. Also uncomment the example_com_cert: section and change it’s configuration to match the domain name you will use with your ALB. Finally you can uncommned the dns: section and Paco will take care of adding the ALB DNS name to your Route 53 Hosted Zone.

Later, if you add a second application behind your ALB, you might have configuration such as:

http:
  port: 80
  protocol: HTTP
  redirect:
    port: 443
    protocol: HTTPS
https:
  port: 443
  protocol: HTTPS
  ssl_certificates:
    - paco.ref netenv.mynet.applications.pypi.groups.shared.resources.example_com_cert
  target_group: pypi
  rules:
    pypi_forward:
      enabled: true
      rule_type: forward
      host: 'pypi.example.com'
      target_group: pypi
      priority: 10
    apptwo_forward:
      enabled: true
      rule_type: forward
      host: 'apptwo.example.com'
      target_group: apptwo
      priority: 20

Monitoring

The netenv/mynet.yaml file starts with monitoring disabled:

# enable/disable web server monitoring
groups:
  pypi:
    resources:
      server:
        monitoring:
          enabled: false # metrics are OFF
          alarm_sets:
            pypiserver:
# enable/disable HTTP checks
monitoring:
  enabled: false # health checks are OFF
  health_checks:
    external_ping:
      enabled: false # health checks are OFF

You can change the monitoring and external_ping sections to enabled: true and then run:

paco provision netenv.mynet.prod

This will install a CloudWatch Agent to gather in-host metrics from the PyPI servers and enable a Route 53 Health Check which will continually ping your server and alert you when it goes down.

There will also be CloudWatch Alarms created for StatusChecks, CPU, Swap and DiskSpace on the root volume.

Also be warned that enabling in-host metrics will change your AutoScalingGroup UserData which will cause new EC2 instance(s) to be launched. In the default configuration this will cause a few minutes downtime for your PyPI server.

Enabling in-host metrics, health checks and alarms will increase your AWS bill by a few dollars a month.

Backups

Your PyPI packages live on an AWS EFS filesystem. This is a very robust and reliable filesystem, however you may still like to maintain regular backups of this filesystem. In your netenv/mynet.yaml find this configuration:

backup_vaults:
  pypi:
    enabled: false # backups are off

And simply change it to enabled: true and run paco provision netenv.mynet.prod.

You can review your backup configuration in the netenv/mynet.yaml file:

backup_vaults:
  pypi:
    enabled: false
    plans:
      ebs:
        title: EFS Backups
        enabled: true
        plan_rules:
          - title: Daily EFS backups
            schedule_expression: cron(0 6 ? * * *)
            lifecycle_delete_after_days: 365
        selections:
          - title: EFS Daily Backups Selection
            tags:
              - condition_type: STRINGEQUALS
                condition_key: Paco-Application-Name
                condition_value: pypi

This default configuration will do daily back-ups at 6 am every day, and keep backups for 365 days.

Questions?

This is only a sample of what you can do with Paco to configure and run an application such as a PyPI server on AWS. This documentation is far from exhaustive, so if you get stuck during installation or configuration, then you’re welcome to jump on the paco-cloud Gitter community and ask us questions.