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SPEC: DNS information as dictionary, adding domain, search domains, options

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Stefan Junker 2016-01-27 11:58:36 +01:00
parent 09214926ea
commit 092e8f5c4d
1 changed files with 34 additions and 11 deletions
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SPEC.md
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@ -50,7 +50,7 @@ The operations that the CNI plugin needs to support are:
- **Name of the interface inside the container**. This is the name that should be assigned to the interface created inside the container (network namespace); consequently it must comply with the standard Linux restrictions on interface names. - **Name of the interface inside the container**. This is the name that should be assigned to the interface created inside the container (network namespace); consequently it must comply with the standard Linux restrictions on interface names.
- Result: - Result:
- **IPs assigned to the interface**. This is either an IPv4 address, an IPv6 address, or both. - **IPs assigned to the interface**. This is either an IPv4 address, an IPv6 address, or both.
- **List of DNS nameservers**. This is a priority-ordered list of IPv4 and IPv6 addresses of DNS nameservers. - **DNS information**. Dictionary that includes DNS information for nameservers, domain, search domains and options.
- Delete container from network - Delete container from network
- Parameters: - Parameters:
@ -91,16 +91,20 @@ Success is indicated by a return code of zero and the following JSON printed to
"gateway": <ipv6-of-the-gateway>, (optional) "gateway": <ipv6-of-the-gateway>, (optional)
"routes": <list-of-ipv6-routes> (optional) "routes": <list-of-ipv6-routes> (optional)
}, },
"dns": <list-of-DNS-nameservers> (optional) "dns": {
"nameservers": <list-of-nameservers> (optional)
"domain": <name-of-local-domain> (optional)
"search": <list-of-additional-search-domains> (optional)
"options": <list-of-options> (optional)
}
} }
``` ```
`cniVersion` specifies a [Semantic Version 2.0](http://semver.org) of CNI specification used by the plugin. `cniVersion` specifies a [Semantic Version 2.0](http://semver.org) of CNI specification used by the plugin.
The "dns" field contains a list of a priority-ordered list of DNS nameservers that this network is aware of. `dns` field contains a dictionary consisting of common DNS information that this network is aware of.
Each entry in the list is a string containing either an IPv4 or an IPv6 address. The result is returned in the same format as specified in the [configuration](#network-configuration).
Typically this value would just be the value returned by the IPAM plugin. The specification does not declare how this information must be processed by CNI consumers.
It is outside the scope of this specification how the container runtime uses the list of DNS nameservers from each of the networks to provide name resolution services to the container. Examples include generating an `/etc/resolv.conf` file to be injected into the container filesystem or running a DNS forwarder on the host.
Examples of how this list could be used include generating an `/etc/resolv.conf` file to be injected into the container filesystem or running a DNS forwarder on the host.
Errors are indicated by a non-zero return code and the following JSON being printed to stdout: Errors are indicated by a non-zero return code and the following JSON being printed to stdout:
``` ```
@ -130,6 +134,11 @@ The network configuration is described in JSON form. The configuration can be st
- `routes` (list): List of subnets (in CIDR notation) that the CNI plugin should ensure are reachable by routing them through the network. Each entry is a dictionary containing: - `routes` (list): List of subnets (in CIDR notation) that the CNI plugin should ensure are reachable by routing them through the network. Each entry is a dictionary containing:
- `dst` (string): subnet in CIDR notation - `dst` (string): subnet in CIDR notation
- `gw` (string): IP address of the gateway to use. If not specified, the default gateway for the subnet is assumed (as determined by the IPAM plugin). - `gw` (string): IP address of the gateway to use. If not specified, the default gateway for the subnet is assumed (as determined by the IPAM plugin).
- `dns`: Dictionary with DNS specific values:
- `nameservers` (list of strings): list of a priority-ordered list of DNS nameservers that this network is aware of. Each entry in the list is a string containing either an IPv4 or an IPv6 address.
- `domain` (string): the local domain used for short hostname lookups.
- `search` (list of strings): list of priority ordered search domains for short hostname lookups. Will be preferred over `domain` by most resolvers.
- `options` (list of strings): list of options that can be passed to the resolver
### Example configurations ### Example configurations
@ -145,6 +154,9 @@ The network configuration is described in JSON form. The configuration can be st
// ipam specific // ipam specific
"subnet": "10.1.0.0/16", "subnet": "10.1.0.0/16",
"gateway": "10.1.0.1" "gateway": "10.1.0.1"
},
"dns": {
"nameservers": [ "10.1.0.1" ]
} }
} }
``` ```
@ -173,6 +185,9 @@ The network configuration is described in JSON form. The configuration can be st
"ipam": { "ipam": {
"type": "dhcp", "type": "dhcp",
"routes": [ { "dst": "10.0.0.0/8", "gw": "10.0.0.1" } ] "routes": [ { "dst": "10.0.0.0/8", "gw": "10.0.0.1" } ]
},
"dns": {
"nameservers": [ "10.0.0.1" ]
} }
} }
``` ```
@ -203,7 +218,12 @@ Success is indicated by a zero return code and the following JSON being printed
"gateway": <ipv6-of-the-gateway>, (optional) "gateway": <ipv6-of-the-gateway>, (optional)
"routes": <list-of-ipv6-routes> (optional) "routes": <list-of-ipv6-routes> (optional)
}, },
"dns": <list-of-DNS-nameservers> (optional) "dns": {
"nameservers": <list-of-nameservers> (optional)
"domain": <name-of-local-domain> (optional)
"search": <list-of-search-domains> (optional)
"options": <list-of-options> (optional)
}
} }
``` ```
@ -216,9 +236,12 @@ Each route entry is a dictionary with the following fields:
- `dst` (string): Destination subnet specified in CIDR notation. - `dst` (string): Destination subnet specified in CIDR notation.
- `gw` (string): IP of the gateway. If omitted, a default gateway is assumed (as determined by the CNI plugin). - `gw` (string): IP of the gateway. If omitted, a default gateway is assumed (as determined by the CNI plugin).
The "dns" field contains a list of a priority-ordered list of DNS nameservers that this network is aware of. The "dns" field contains a dictionary consisting of common DNS information.
Each entry in the list is a string containing either an IPv4 or an IPv6 address. - `nameservers` (list of strings): list of a priority-ordered list of DNS nameservers that this network is aware of. Each entry in the list is a string containing either an IPv4 or an IPv6 address.
See [CNI Plugin Result](#result) section for details. - `domain` (string): the local domain used for short hostname lookups.
- `search` (list of strings): list of priority ordered search domains for short hostname lookups. Will be preferred over `domain` by most resolvers.
- `options` (list of strings): list of options that can be passed to the resolver
See [CNI Plugin Result](#result) section for more information.
Errors and logs are communicated in the same way as the CNI plugin. See [CNI Plugin Result](#result) section for details. Errors and logs are communicated in the same way as the CNI plugin. See [CNI Plugin Result](#result) section for details.