https://github.com/bpineau/cloud-floating-ip
Implement a cloud floating/virtual IP by configuring GCP or AWS routes
https://github.com/bpineau/cloud-floating-ip
aws ec2 floating gce gcp golang vip
Last synced: 3 months ago
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Implement a cloud floating/virtual IP by configuring GCP or AWS routes
- Host: GitHub
- URL: https://github.com/bpineau/cloud-floating-ip
- Owner: bpineau
- License: mit
- Created: 2018-03-06T07:00:12.000Z (about 7 years ago)
- Default Branch: master
- Last Pushed: 2018-03-19T07:48:07.000Z (about 7 years ago)
- Last Synced: 2024-06-20T11:45:50.397Z (10 months ago)
- Topics: aws, ec2, floating, gce, gcp, golang, vip
- Language: Go
- Homepage:
- Size: 49.8 KB
- Stars: 5
- Watchers: 4
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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# cloud-floating-ip
Implement a floating/virtual IP by configuring cloud provider's routes.
Choose an arbitrary private IP address, and `cloud-floating-ip` will
configure route for that IP to the AWS or GCP instance of your choice.
## Instances preparation
To choose a virtual IP: this address must be available, and not used
elsewhere in the VPC; it doesn't have to be part of an existing subnet range.
All EC2/GCE instances that may become "primary" (carry the floating IP)
at some point should be allowed by the cloud provider to route traffic:
`SourceDestCheck` (EC2) or `canIpForward` (GCE) must be enabled.
Those instances should be able to accept traffic to the floating IP.
To that effect, we can assign the virtual IP address to a loopback or
a dummy interface on all instances:
```bash
# we can do that on all instances
ip link add dummy0 type dummy
ip address add 10.200.0.50/32 dev dummy0
ip link set dev dummy0 up
```
This can be persisted in network configurations (eg. in /etc/network/interfaces
or /etc/sysconfig/network-scripts/).
## Usage
To route the floating IP to the current instance:
```bash
# see what would change
cloud-floating-ip -i 10.200.0.50 preempt --dry-run
# apply the changes
cloud-floating-ip -i 10.200.0.50 preempt
```
The IP can be preempted by other instances in the VPC, by using the same
`preempt` command.
To verify the status ("primary" or "standby") of any instance:
```bash
cloud-floating-ip -i 10.200.0.50 status
```
When `cloud-floating-ip` runs on the target instance, most settings (region,
instance id, cloud provider, ...) can be guessed from the instance metadata.
To act on a remote instance, we must be more explicit (or use a configuration file). Eg:
```bash
cloud-floating-ip -o aws -i 10.200.0.50 -t i-0e3f4ac17545ce580 -r eu-west-1 status
cloud-floating-ip -o aws -i 10.200.0.50 -t i-0e3f4ac17545ce580 -r eu-west-1 preempt
cloud-floating-ip -o gce -i 10.200.0.50 -p my-gcp-project \
-t my-gce-instance -z europe-west1-b status
````
To store the configuration (and save repetitive `-i ...` arguments):
```bash
cat< /etc/cloud-floating-ip.yaml
ip: 10.200.0.50
quiet: true
EOF
```
## Multihomed instances
When the instance has only one interface attached to the VPC, `cloud-floating-ip`
will find and use this interface automatically.
If the instance has more than one external interfaces (and/or networks), we need
one of the following options to choose the target interface we'll route traffic to:
Provide either:
* --interface : the target interface name (ie. eni-xxxx on AWS, nicX on GCE)
* --subnet : the target network interface's subnet name
* --target-ip : the target network interface's private IP
## Options
The `ip` argument is mandatory. Other settings can be collected from instance's
metadata when running `cloud-floating-ip` from an AWS or GCE instance.
Those settings can be stored in the `/etc/cloud-floating-ip.yaml`
configuration file. You can also pass them through environments (upper
case, prefixed by `CFI_`).
```
Usage:
cloud-floating-ip [flags]
cloud-floating-ip [command]
Available Commands:
destroy Delete the routes managed by cloud-floating-ip
help Help about any command
preempt Preempt an IP address and route it to the instance
status Display the status of the instance (owner or standby)
Flags:
-c, --config string config file (default is /etc/cloud-floating-ip.yaml)
-i, --ip string IP address
-d, --dry-run dry-run mode
-q, --quiet quiet mode
-h, --help help for cloud-floating-ip
-o, --hoster string hosting provider (aws or gce)
-t, --instance string instance name
-f, --interface string network interface ID
-s, --subnet string subnet ID
-g, --target-ip string target private IP
-m, --ignore-main-table (AWS) ignore routes in main table
-a, --aws-access-key-id string (AWS) access key Id
-k, --aws-secret-key string (AWS) secret key
-r, --region string (AWS) region name
-b, --table strings (AWS) only consider this route table (may be specified several times)
-p, --project string (GCP) project id
-z, --zone string (GCP) zone name
```
## Required privileges
On EC2, the account running `cloud-floating-ip` must have the following rights:
```
ec2:DescribeInstances
ec2:DescribeRouteTables
ec2:CreateRoute
ec2:ReplaceRoute
ec2:DeleteRoute
```
On GCE:
```
compute.instances.get
compute.routes.get
compute.routes.create
compute.routes.delete
container.operations.get
container.operations.list
```
## Limitations
* On GCE, `cloud-floating-ip` won't delete already created, pre-existing routes with a distinct custom name
* IPv4 only, for now