whentimeslows/website
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

fix: add dns search record limit note. (#18913)

Browse Source
This commit is contained in:
Jacky Wu
2020-02-08 03:31:46 +08:00
committed by GitHub
parent ecda7af470
commit b9ff4f1bf8
1 changed files with 1 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
content/en/docs/tasks/administer-cluster/dns-debugging-resolution.md
+1 -8
View File
@@ -258,14 +258,7 @@ Kubernetes installs do not configure the nodes' `resolv.conf` files to use the
cluster DNS by default, because that process is inherently distribution-specific. cluster DNS by default, because that process is inherently distribution-specific.
This should probably be implemented eventually. This should probably be implemented eventually.
Linux's libc is impossibly stuck ([see this bug from Linux's libc (a.k.a. glibc) has a limit for the DNS `nameserver` records to 3 by default. What's more, for the glibc versions which are older than glic-2.17-222 ([the new versions update see this issue](https://access.redhat.com/solutions/58028)), the DNS `search` records has been limited to 6 ([see this bug from 2005](https://bugzilla.redhat.com/show_bug.cgi?id=168253)). Kubernetes needs to consume 1 `nameserver` record and 3 `search` records. This means that if a local installation already uses 3 `nameserver`s or uses more than 3 `search`es while your glibc versions in the affected list, some of those settings will be lost. For the workaround of the DNS `nameserver` records limit, the node can run `dnsmasq` which will provide more `nameserver` entries, you can also use kubelet's `--resolv-conf` flag. For fixing the DNS `search` records limit, consider upgrading your linux distribution or glibc version.
2005](https://bugzilla.redhat.com/show_bug.cgi?id=168253)) with limits of just
3 DNS `nameserver` records and 6 DNS `search` records. Kubernetes needs to
consume 1 `nameserver` record and 3 `search` records. This means that if a
local installation already uses 3 `nameserver`s or uses more than 3 `search`es,
some of those settings will be lost. As a partial workaround, the node can run
`dnsmasq` which will provide more `nameserver` entries, but not more `search`
entries. You can also use kubelet's `--resolv-conf` flag.
If you are using Alpine version 3.3 or earlier as your base image, DNS may not If you are using Alpine version 3.3 or earlier as your base image, DNS may not
work properly owing to a known issue with Alpine. work properly owing to a known issue with Alpine.