aliaser

aliaser v0.02

Copyright ©2017 Josh Wieder

http://www.joshwieder.net/

josh.wieder@live.com

PGP Key 0x30D2ABDB2DF72435

A service written in bash to resolve ongoing issues with IP aliasing when using Amazon EC2 virtual machines without the benefit of ec2-net-utils.

###Features

• Adds and removes routing table entries on RHEL Amazon EC2 virtual machines to support the mapping of multiple public IP addresses to the same EC2 instance.

• Prints secondary public and private IP addresses mappings

• Routing table is stored in memory, allowing greater flexibility with storage options

• Multiple IP mappings are supported

###To Do

The following features are planned:

• RPM installation

• Integration with ec2-api-tools

Instructions for Red Hat Linux using systemd

1. Ensure that you have assigned your preferred secondary private IP and secondary Elastic IP to your instance as outlined here

2. Replicate aliaser using git or download as a .zip file

3. On your server, copy the systemd service file aliaser.service to /etc/systemd/system/aliaser.service

4. Copy the shell script aliaser to /usr/bin/aliaser

5. Assign the script an executable bit to the shell script as follows:

   `#chmod +x /usr/bin/aliaser`
   

6. aliaser will is now installed! Start the aliaser service:

   #systemctl start aliaser.service

7. Configure your server to load aliaser at boot:

   #systemctl enable aliaser.service

8. aliaser will now load at boot time and can be managed like any other systemd service:

| Command | Description | | -------------------------------------- |:------------------------------------:| | #systemctl start aliaser.service | Start aliaser service | | #systemctl stop aliaser.service | Stop aliaser service | | #systemctl restart aliaser.service | Restart aliaser service |
| #systemctl disable aliaser.service | Prevent aliaser from loading at boot | | #systemctl -l status aliaser.service | View the status of aliaser service |

9. Execute aliaser as a shell script using one of a variety of commands:

| Command | Description | | ------------------------ |:--------------------------------------------------------------------------------------------:| | ./aliaser -h | Prints list of commands | | ./aliaser version | Prints version and copyright information | | sudo ./aliaser start | Adds routes for secondary IPs to the routing table |
| sudo ./aliaser restart | Adds routes for secondary IPs to the routing table (ATM for service execution purposes only) | | sudo ./aliaser stop | Removes secondary IP routers and restarts network service | | /aliaser print | Prints list of secondary private and Public IP address assigned to this instance | | /aliaser test | Verifies route additions by querying an outside host |

Bugs & Known Issues

The output of curl http://169.254.169.254/latest/meta-data/public-ipv4 has proven unpredictable. Unfortunately the Primary Public IP filed for ./aliaser print initially relied on this EC2 API call. I am working on formatting another option that will produce stable output. This does not impact the actual functionality of the IP address allocation.

Licensing and Copyright

Copyright ©2017 Josh Wieder

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.