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ipam/host-local: support multiple IP ranges

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This change allows the host-local allocator to allocate multiple IPs.
This is intended to enable dual-stack, but is not limited to only two
subnets or separate address families.
This commit is contained in:
Casey Callendrello
2017-05-11 17:01:20 +02:00
parent 7cda9af13f
commit 2e9e87732f
13 changed files with 1454 additions and 484 deletions
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82
plugins/ipam/host-local/README.md
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@ -5,30 +5,41 @@ it can include a DNS configuration from a `resolv.conf` file on the host.
## Overview
host-local IPAM plugin allocates IPv4 addresses out of a specified address range.
host-local IPAM plugin allocates ip addresses out of a set of address ranges.
It stores the state locally on the host filesystem, therefore ensuring uniqueness of IP addresses on a single host.
## Example configurations
IPv4:
```json
{
"ipam": {
"type": "host-local",
"subnet": "10.10.0.0/16",
"rangeStart": "10.10.1.20",
"rangeEnd": "10.10.3.50",
"gateway": "10.10.0.254",
"ranges": [
{
"subnet": "10.10.0.0/16",
"rangeStart": "10.10.1.20",
"rangeEnd": "10.10.3.50",
"gateway": "10.10.0.254"
},
{
"subnet": "3ffe:ffff:0:01ff::/64",
"rangeStart": "3ffe:ffff:0:01ff::0010",
"rangeEnd": "3ffe:ffff:0:01ff::0020"
}
],
"routes": [
{ "dst": "0.0.0.0/0" },
{ "dst": "192.168.0.0/16", "gw": "10.10.5.1" }
{ "dst": "192.168.0.0/16", "gw": "10.10.5.1" },
{ "dst": "3ffe:ffff:0:01ff::1/64" }
],
"dataDir": "/var/my-orchestrator/container-ipam-state"
"dataDir": "/run/my-orchestrator/container-ipam-state"
}
}
```
IPv6:
Previous versions of the `host-local` allocator did not support the `ranges`
property, and instead expected a single range on the top level. This is
deprecated but still supported.
```json
{
"ipam": {
@ -47,36 +58,65 @@ IPv6:
We can test it out on the command-line:
```bash
$ export CNI_COMMAND=ADD
$ export CNI_CONTAINERID=f81d4fae-7dec-11d0-a765-00a0c91e6bf6
$ echo '{ "name": "default", "ipam": { "type": "host-local", "subnet": "203.0.113.0/24" } }' | ./host-local
$ echo '{ "cniVersion": "0.3.1", "name": "examplenet", "ipam": { "type": "host-local", "ranges": [ {"subnet": "203.0.113.0/24"}, {"subnet": "2001:db8:1::/64"}], "dataDir": "/tmp/cni-example" } }' | CNI_COMMAND=ADD CNI_CONTAINERID=example CNI_NETNS=/dev/null CNI_IFNAME=dummy0 CNI_PATH=. ./host-local
```
```json
{
"ip4": {
"ip": "203.0.113.1/24"
}
"ips": [
{
"version": "4",
"address": "203.0.113.2/24",
"gateway": "203.0.113.1"
},
{
"version": "6",
"address": "2001:db8:1::2/64",
"gateway": "2001:db8:1::1"
}
],
"dns": {}
}
```
## Network configuration reference
* `type` (string, required): "host-local".
* `subnet` (string, required): CIDR block to allocate out of.
* `rangeStart` (string, optional): IP inside of "subnet" from which to start allocating addresses. Defaults to ".2" IP inside of the "subnet" block.
* `rangeEnd` (string, optional): IP inside of "subnet" with which to end allocating addresses. Defaults to ".254" IP inside of the "subnet" block.
* `gateway` (string, optional): IP inside of "subnet" to designate as the gateway. Defaults to ".1" IP inside of the "subnet" block.
* `routes` (string, optional): list of routes to add to the container namespace. Each route is a dictionary with "dst" and optional "gw" fields. If "gw" is omitted, value of "gateway" will be used.
* `resolvConf` (string, optional): Path to a `resolv.conf` on the host to parse and return as the DNS configuration
* `dataDir` (string, optional): Path to a directory to use for maintaining state, e.g. which IPs have been allocated to which containers
* `ranges`, (array, required, nonempty) an array of range objects:
* `subnet` (string, required): CIDR block to allocate out of.
* `rangeStart` (string, optional): IP inside of "subnet" from which to start allocating addresses. Defaults to ".2" IP inside of the "subnet" block.
* `rangeEnd` (string, optional): IP inside of "subnet" with which to end allocating addresses. Defaults to ".254" IP inside of the "subnet" block for ipv4, ".255" for IPv6
* `gateway` (string, optional): IP inside of "subnet" to designate as the gateway. Defaults to ".1" IP inside of the "subnet" block.
Older versions of the `host-local` plugin did not support the `ranges` array. Instead,
all the properties in the `range` object were top-level. This is still supported but deprecated.
## Supported arguments
The following [CNI_ARGS](https://github.com/containernetworking/cni/blob/master/SPEC.md#parameters) are supported:
* `ip`: request a specific IP address from the subnet. If it's not available, the plugin will exit with an error
* `ip`: request a specific IP address from a subnet.
The following [args conventions](https://github.com/containernetworking/cni/blob/master/CONVENTIONS.md) are supported:
* `ips` (array of strings): A list of custom IPs to attempt to allocate
### Custom IP allocation
For every requested custom IP, the `host-local` allocator will request that IP
if it falls within one of the `range` objects. Thus it is possible to specify
multiple custom IPs and multiple ranges.
If any requested IPs cannot be reserved, either because they are already in use
or are not part of a specified range, the plugin will return an error.
## Files
Allocated IP addresses are stored as files in `/var/lib/cni/networks/$NETWORK_NAME`. The prefix can be customized with the `dataDir` option listed above.
Allocated IP addresses are stored as files in `/var/lib/cni/networks/$NETWORK_NAME`.
The path can be customized with the `dataDir` option listed above. Environments
where IPs are released automatically on reboot (e.g. running containers are not
restored) may wish to specify `/var/run/cni` or another tmpfs mounted directory
instead.