discovery

Documentation

Overview

Package discovery contains functionality to discover the type of etcd used in back up and restore operations as well as what Kubernetes distro is used.

Index

• func CountKeysFor(endpoint string, distro types.KubernetesDistro) (int, int, error)
• func ProbeEtcd(endpoint string) (string, bool, error)
• func ProbeKubernetesDistro(endpoint string) (types.KubernetesDistro, error)
• func Visit2(kapi client.KeysAPI, path string, fn types.Reap) error
• func Visit3(c3 *clientv3.Client, path string, distro types.KubernetesDistro, fn types.Reap) error

Examples

• CountKeysFor
• ProbeEtcd
• ProbeKubernetesDistro

Functions

func CountKeysFor

func CountKeysFor(endpoint string, distro types.KubernetesDistro) (int, int, error)

CountKeysFor iterates over well-known keys of a given Kubernetes distro and returns the number of keys and their values total size, in the respective key range/subtree.

Example

Shows how to glean stats from etcd by walking well-known keys of a given Kubernetes distro. It assumes that the etcd process is servering on 127.0.0.1:2379 and the vanilla Kubernetes distro is using it.

// define the URL etcd is available at:
etcdurl := "http://127.0.0.1:2379"

// carry out the stats walk and handle errors as they occur:
numkeys, totalsize, err := CountKeysFor(etcdurl, types.Vanilla)
if err != nil {
	log.Fatal(err)
	return
}
fmt.Printf("Found %d keys and overall payload size of %d bytes.\n", numkeys, totalsize)

Output:

Found 1024 keys and overall payload size of 350876 bytes.

func ProbeEtcd

func ProbeEtcd(endpoint string) (string, bool, error)

ProbeEtcd probes an endpoint at path /version to figure which version of etcd it is and in which mode (secure or insecure) it is used.

Example

Shows how to probe etcd to determine which version is running and in which mode (secure or insecure) it is used. It assumes that the etcd process is servering on 127.0.0.1:2379.

// define the URL etcd is available at:
etcdurl := "http://127.0.0.1:2379"

// carry out the probe and handle errors as they occur:
version, secure, err := ProbeEtcd(etcdurl)
if err != nil {
	log.Fatal(err)
	return
}
fmt.Printf("Discovered etcd in version %s, running in secure mode: %t\n", version, secure)

Output:

Discovered etcd in version 3.1.0, running in secure mode: false

func ProbeKubernetesDistro

func ProbeKubernetesDistro(endpoint string) (types.KubernetesDistro, error)

ProbeKubernetesDistro probes an etcd cluster for which Kubernetes distribution is present by scanning the available keys.

Example

Shows how to probe etcd to determine which Kubernetes distribution is present (if at all) by scanning the available keys. It assumes that the etcd process is servering on 127.0.0.1:2379 and the OpenShift Kubernetes distro is using it.

// define the URL etcd is available at:
etcdurl := "http://127.0.0.1:2379"

// a textual description of the Kubernetes distro
var distro string

// carry out the probe and handle errors as they occur:
distrotype, err := ProbeKubernetesDistro(etcdurl)
if err != nil {
	log.Fatal(err)
	return
}
switch distrotype {
case types.Vanilla:
	distro = "Vanilla Kubernetes"
case types.OpenShift:
	distro = "OpenShift"
default:
	distro = "no Kubernetes distro found"
}
fmt.Printf("Discovered Kubernetes distro: %s\n", distro)

Output:

Discovered Kubernetes distro: OpenShift

func Visit2

func Visit2(kapi client.KeysAPI, path string, fn types.Reap) error

Visit2 recursively visits an etcd2 server from the root and applies the reap function on leaf nodes (keys that don't have sub-keys), otherwise descents the tree.

func Visit3

func Visit3(c3 *clientv3.Client, path string, distro types.KubernetesDistro, fn types.Reap) error

Visit3 visits all paths of an etcd3 server and applies the reap function on the keys.