diff options
Diffstat (limited to 'man/coredns-autopath.7')
| -rw-r--r-- | man/coredns-autopath.7 | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/man/coredns-autopath.7 b/man/coredns-autopath.7 index 4bacee73f..f94c48b47 100644 --- a/man/coredns-autopath.7 +++ b/man/coredns-autopath.7 @@ -1,5 +1,5 @@ .\" Generated by Mmark Markdown Processer - mmark.miek.nl -.TH "COREDNS-AUTOPATH" 7 "January 2020" "CoreDNS" "CoreDNS Plugins" +.TH "COREDNS-AUTOPATH" 7 "March 2020" "CoreDNS" "CoreDNS Plugins" .SH "NAME" .PP @@ -13,6 +13,9 @@ failures, the original reply is returned. Because \fIautopath\fP returns a reply the original question it will add a CNAME that points from the original name (with the search path element in it) to the name of this answer. +.PP +\fBNote\fP: There are several known issues. See section below. + .SH "SYNTAX" .PP .RS @@ -39,7 +42,7 @@ If a plugin implements the \fB\fCAutoPather\fR interface then it can be used. If monitoring is enabled (via the \fIprometheus\fP plugin) then the following metric is exported: .IP \(bu 4 -\fB\fCcoredns_autopath_success_count_total{server}\fR - counter of successfully autopath-ed queries. +\fB\fCcoredns_autopath_success_total{server}\fR - counter of successfully autopath-ed queries. .PP @@ -73,8 +76,19 @@ Use the search path dynamically retrieved from the \fIkubernetes\fP plugin. .SH "KNOWN ISSUES" .PP -In Kubernetes, \fIautopath\fP is not compatible with pods running from Windows nodes. +In Kubernetes, \fIautopath\fP can derive the wrong namespace of a client Pod (and therefore wrong search path) +in the following case. To properly build the search path of a client \fIautopath\fP needs to +know the namespace of the a Pod making a DNS request. To do this, it relies on the +\fIkubernetes\fP plugin's Pod cache to resolve the client's IP address to a Pod. The Pod cache is maintained by +an API watch on Pods. When Pod IP assignments change, the Kubernetes API notifies CoreDNS via the API watch. +However, that notification is not instantaneous. In the case that a Pod is deleted, and it's IP is +immediately provisioned to a Pod in another namespace, and that new Pod make a DNS lookup \fIbefore\fP the API watch +can notify CoreDNS of the change, \fIautopath\fP will resolve the IP to the previous Pod's namespace. + +.PP +In Kubernetes, \fIautopath\fP is not compatible with Pods running from Windows nodes. .PP -If the server side search ultimately results in a negative answer (e.g. \fB\fCNXDOMAIN\fR), then the client will fruitlessly search all paths manually, thus negating the \fIautopath\fP optimization. +If the server side search ultimately results in a negative answer (e.g. \fB\fCNXDOMAIN\fR), then the client will +fruitlessly search all paths manually, thus negating the \fIautopath\fP optimization. |