epostnikof/kubespray
1
0
Fork 0
mirror of https://github.com/kubernetes-sigs/kubespray.git synced 2025-12-14 13:54:37 +03:00
Code Issues Packages Projects Releases Wiki Activity

Merge branch 'master' into tags_download

Browse Source
This commit is contained in:
Bogdan Dobrelya
2016-12-12 11:44:00 +01:00
committed by GitHub
parent fd9b26675e b1e852a785
commit 774f4dbbf7
23 changed files with 248 additions and 124 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
docs/ansible.md
View File

@@ -62,6 +62,7 @@ The following tags are defined in playbooks:
| canal | Network plugin Canal
| cloud-provider | Cloud-provider related tasks
| dnsmasq | Configuring DNS stack for hosts and K8s apps
| docker | Configuring docker for hosts
| download | Fetching container images to a delegate host
| etcd | Configuring etcd cluster
| etcd-pre-upgrade | Upgrading etcd cluster

25
docs/dns-stack.md
View File

@@ -1,15 +1,24 @@
K8s DNS stack by Kargo
======================
Kargo configures a [Kubernetes DNS](http://kubernetes.io/docs/admin/dns/)
For K8s cluster nodes, kargo configures a [Kubernetes DNS](http://kubernetes.io/docs/admin/dns/)
[cluster add-on](http://releases.k8s.io/master/cluster/addons/README.md)
to serve as an authoritative DNS server for a given ``dns_domain`` and its
``svc, default.svc`` default subdomains (a total of ``ndots: 5`` max levels).
Note, additional search (sub)domains may be defined in the ``searchdomains``
Other nodes in the inventory, like external storage nodes or a separate etcd cluster
node group, considered non-cluster and left up to the user to configure DNS resolve.
Note, custom ``ndots`` values affect only the dnsmasq daemon set (explained below).
While the kubedns has the ``ndots=5`` hardcoded, which is not recommended due to
[DNS performance reasons](https://github.com/kubernetes/kubernetes/issues/14051).
You can use config maps for the kubedns app to workaround the issue, which is
yet in the Kargo scope.
Additional search (sub)domains may be defined in the ``searchdomains``
and ``ndots`` vars. And additional recursive DNS resolvers in the `` upstream_dns_servers``,
``nameservers`` vars. Intranet DNS resolvers should be specified in the first
place, followed by external resolvers, for example:
``nameservers`` vars. Intranet/cloud provider DNS resolvers should be specified
in the first place, followed by external resolvers, for example:
```
skip_dnsmasq: true
@@ -21,7 +30,13 @@ or
skip_dnsmasq: false
upstream_dns_servers: [172.18.32.6, 172.18.32.7, 8.8.8.8, 8.8.8.4]
```
The vars are explained below as well.
The vars are explained below. For the early cluster deployment stage, when there
is yet K8s cluster and apps exist, a user may expect local repos to be
accessible via authoritative intranet resolvers. For that case, if none custom vars
was specified, the default resolver is set to either the cloud provider default
or `8.8.8.8`. And domain is set to the default ``dns_domain`` value as well.
Later, the nameservers will be reconfigured to the DNS service IP that Kargo
configures for K8s cluster.
DNS configuration details
-------------------------