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community-catalog/templates/coredns/0/README.md
Jason-ZW fde452c869 Catalog for CoreDNS cattle orchestration.
2018-03-02 01:39:45 +08:00

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CoreDNS

CoreDNS (written in Go) chains plugins. Each plugin performs a DNS function.

CoreDNS is a Cloud Native Computing Foundation incubating level project.

CoreDNS is a fast and flexible DNS server. The keyword here is flexible: with CoreDNS you are able to do what you want with your DNS data by utilizing plugins. If some functionality is not provided out of the box you can add it by writing a plugin.

And more. Each of the plugins is documented. See coredns.io/plugins for all in-tree plugins, and coredns.io/explugins for all out-of-tree plugins.

Dockerfile

The Dockerfile source is under below: https://github.com/Jason-ZW/Dockerfile/tree/master/coredns

Parameters

  • Publish port: Port to publish coredns service. (eg. 53)
  • DNS zone names: you can put multiple zone names.（eg. rancher.io,rancher.io,172.in-addr.arpa）
  • Etcd root path: etcd root path which is used to save records. (eg. /skydns)
  • Etcd endpoints: etcd service endpoints，this catalog don't include etcd service,please use external etcd service. (eg. http://localhost:2379, endpoints2, ...)
  • UpStream for dns: upstream configuration for dns server. (eg. /etc/resolv.conf)
  • Forward addresses: the address which to be forwarded DNS query. (eg. 8.8.8.8:53,8.8.4.4:53)
  • Prometheus plugin support: whether to enable prometheus plugin.
  • Errors plugin support: whether to enable errors plugin.
  • Log plugin support: whether to enable log plugin.
  • Proxy plugin support: whether to enable proxy plugin.
  • Cache plugin support: whether to enable cache plugin.
  • Loadbalance plugin support: whether to enable loadbalance plugin.

More detail for CoreDNS plugin https://coredns.io/plugins

Guide

Serve for DNS A/AAAA Records:

Put DNS A record to etcd server.

curl -XPUT http://{ETCD_ENDPOINT}:2379/v2/keys/skydns/io/rancher/busybox -d value='{"host":"172.16.80.175","port":8080}'

Set nameserver to /etc/resolv.conf.

nameserver {DNS_SERVER_ADDRESS}
search rancher.io

Query DNS use dns tools(eg. dig or nslookup)

nslookup busybox.rancher.io

#output:
Server:		xxx.xxx.xxx.xxx
Address:	xxx.xxx.xxx.xxx#53

Name:	busybox.rancher.io
Address: 172.16.80.175

Serve for DNS PTR Records:

Modify the DNS zone names section on Catalog template.

# DNS zone names section on Catalog template.
rancher.io,172.in-addr.arpa

Put DNS PTR record to etcd server.

curl -XPUT http://{ETCD_ENDPOINT}:2379/v2/keys/skydns/arpa/in-addr/172/16/80/175 -d value='{"host":"busybox.rancher.io"}'

Set nameserver to /etc/resolv.conf.

nameserver {DNS_SERVER_ADDRESS}
search rancher.io

Query DNS use dns tools(eg. dig or nslookup)

dig @localhost -x 172.16.80.175 +short

#output:
busybox.rancher.io.

Community

We're most active on Slack (and Github):

More resources can be found:

Notice: For kubernetes, please use helm coredns's chart.