IPAM
Description
In order to avoid IP collisions in the system and ensure a proper IPs distribution, this service is offering some IPAM functionalities that can be consumed using a kubernetes clusterIP service (over the kubernetes primary network). This IPAM Service is a GRPC server listening on port 7777.
The specifications of the IPAM Service are written in a proto file accessible here.
IP/Prefix distribution granularity
The Meridio IPAM distributes IP/Prefixes (always within the trench subnet defined in the configuration by IPAM_PREFIX_IPV4 and IPAM_PREFIX_IPV6) at a few different levels.
The first one is at the conduit level. Represented in blue (Conduit-A) and in red (Conduit-B) in the picture below, they are allocated automatically by the IPAM by watching the conduit list via the NSP service. The conduit subnet prefix lengths are defined in the configuration by IPAM_CONDUIT_PREFIX_LENGTH_IPV4 and IPAM_CONDUIT_PREFIX_LENGTH_IPV6.
The second one is at the node level. Represented in black in the picture below (1 per node per conduit), they are allocated when the Allocate API function is called (note: there is currently no way to unallocate except if the conduit is removed.). The node subnet prefix lengths are defined in the configuration by IPAM_NODE_PREFIX_LENGTH_IPV4 and IPAM_NODE_PREFIX_LENGTH_IPV6.
The third (last one) is at the pod level. Each pod will get assigned a unique IP address with IPAM_NODE_PREFIX_LENGTH_IPV4 or IPAM_NODE_PREFIX_LENGTH_IPV6 as prefix length.
Picture representing a cluster with 2 nodes (worked-A and worker-B), 2 conduits (Conduit-A and Conduit-B), 4 targets and the corresponding subnets.
- Target-1 is running on worker-A and connected to Conduit-A
- Target-2 is running on worker-A and connected to Conduit-B
- Target-3 is running on worker-B and connected to Conduit-A and Conduit-B
- Target-4 is running on worker-B and connected to Conduit-B
Data persistence
Running as StatefulSet with a single replica, the IPAM handles restarts and pod deletions by saving the data in a local sqlite stored in a persistent volume requested via a volumeClaimTemplates.
Configuration
https://github.com/Nordix/Meridio/blob/master/cmd/ipam/config.go
| Environment variable | Type | Description | Default |
|---|---|---|---|
| IPAM_PORT | int | Port the pod is running the service | 7777 |
| IPAM_DATA_SOURCE | string | Path and file name of the sqlite database | /run/ipam/data/registry.db |
| IPAM_TRENCH_NAME | string | Trench the pod is running on | |
| IPAM_NSP_SERVICE | string | IP (or domain) and port of the NSP Service | |
| IPAM_PREFIX_IPV4 | string | IPv4 prefix from which the proxy prefixes will be allocated | 169.255.0.0/16 |
| IPAM_CONDUIT_PREFIX_LENGTH_IPV4 | int | Conduit prefix length which will be allocated | 20 |
| IPAM_NODE_PREFIX_LENGTH_IPV4 | int | node prefix length which will be allocated | 24 |
| IPAM_PREFIX_IPV6 | string | IPv6 prefix from which the proxy prefixes will be allocated | fd00::/48 |
| IPAM_CONDUIT_PREFIX_LENGTH_IPV6 | int | Conduit prefix length which will be allocated | 56 |
| IPAM_NODE_PREFIX_LENGTH_IPV6 | int | node prefix length which will be allocated | 64 |
| IPAM_IP_FAMILY | string | IP family (ipv4, ipv6, dualstack) | dualstack |
| IPAM_LOG_LEVEL | string | Log level (TRACE, DEBUG, INFO, WARNING, ERROR, FATAL, PANIC) | DEBUG |
Command Line
| Command | Action | Default |
|---|---|---|
| --help | Display a help describing | |
| --version | Display the version |
Communication
Here are all components the ipam is communicating with:
| Component | Secured | Method | Description |
|---|---|---|---|
| Spire | TBD | Unix Socket | Obtain and validate SVIDs |
| NSP Service | yes (mTLS) | TCP | Watch configuration |
An overview of the communications between all components is available here.
Health check
The health check is provided by the GRPC Health Checking Protocol. The status returned can be UNKNOWN, SERVING, NOT_SERVING or SERVICE_UNKNOWN.
| Service | Description |
|---|---|
| Liveness | A unique service to be used by liveness probe to return status, can aggregate other lesser services |
| Readiness | A unique service to be used by readiness probe to return status, can aggregate other lesser services |
| Service | Probe | Description |
|---|---|---|
| NSPCli | Readiness | Monitor status of the connection to the NSP service |
| IPAM | Liveness | Monitor status of the server |
Privileges
No privileges required.