ipam/host-local: support sets of disjoint ranges

In real-world address allocations, disjoint address ranges are common.
Therefore, the host-local allocator should support them.

This change still allows for multiple IPs in a single configuration, but
also allows for a "set of subnets."

Fixes: #45
This commit is contained in:
Casey Callendrello
2017-07-31 14:38:11 +02:00
parent 20bc33abc5
commit 27d027a6d3
13 changed files with 784 additions and 518 deletions

View File

@ -8,24 +8,40 @@ it can include a DNS configuration from a `resolv.conf` file on the host.
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.
The allocator can allocate multiple ranges, and supports sets of multiple (disjoint)
subnets. The allocation strategy is loosely round-robin within each range set.
## Example configurations
Note that the key `ranges` is a list of range sets. That is to say, the length
of the top-level array is the number of addresses returned. The second-level
array is a set of subnets to use as a pool of possible addresses.
This example configuration returns 2 IP addresses.
```json
{
"ipam": {
"type": "host-local",
"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"
}
[
{
"subnet": "10.10.0.0/16",
"rangeStart": "10.10.1.20",
"rangeEnd": "10.10.3.50",
"gateway": "10.10.0.254"
},
{
"subnet": "172.16.5.0/24"
}
],
[
{
"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" },
@ -58,7 +74,7 @@ deprecated but still supported.
We can test it out on the command-line:
```bash
$ 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
$ 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
```
@ -86,7 +102,7 @@ $ echo '{ "cniVersion": "0.3.1", "name": "examplenet", "ipam": { "type": "host-l
* `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:
* `ranges`, (array, required, nonempty) an array of arrays 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