{{tag>Brouillon}}

= Notes etcd

Voir aussi :
* [[Notes CouchDB|CouchDB]]


== Intro


* https://etcd.io/
* https://etcd.io/docs/v3.5/dev-guide/interacting_v3/
* https://www.ionos.fr/digitalguide/hebergement/aspects-techniques/quest-ce-quetcd/
* https://www.blackcreeper.com/kubernetes/etcd-decouverte-et-premiers-pas/

== Install

* http://play.etcd.io/install
* https://www.digitalocean.com/community/tutorials/how-to-set-up-and-secure-an-etcd-cluster-with-ansible-on-ubuntu-18-04-fr
* https://docs.okd.io/3.11/admin_guide/assembly_replace-etcd-member.html

<code bash>
apt install etcd-client
apt-get install etcd
</code>

== Config

=== Droits

https://etcd.io/docs/v3.5/demo/

== Exemples basiques

Lancement
<code bash>
etcd
</code>


Connexion
<code bash>
etcdctl --endpoints http://127.0.0.1:2379 get /
</code>


Put
<code bash>
etcdctl put greeting "Hello, etcd"
</code>

Get
<code bash>
ETCDCTL_API=3 etcdctl get greeting
etcdctl get foo --print-value-only
etcdctl get --prefix --rev=4 foo
etcdctl watch foo --hex
</code>

<code bash>
etcdctl --no-sync --peers https//plop1.lan:10835,https//plop2.lan:10836 -u username:password ls /

alias e='etcdctl --ca-file ~/compose_etcd.pk --no-sync --peers https://aws-us-east-1-portal10.dblayer.com:10835,https://aws-us-east-1-portal11.dblayer.com:27265 -u root:*********'
</code>

<code bash>
etcdctl mk x 3
etcdctl mk y 123
etcdctl ls
etcdctl get /y
etcdctl set new 6
etcdctl set d/a 4
etcdctl set d/b 5
etcdctl ls d
etcdctl rm --recursive d

# TTL of 5 seconds
etcdctl mk e 4 --ttl "5"
</code>

<code bash>
export ETCDCTL_API=3
export ETCDCTL_ENDPOINTS=$(minikube service example-etcd-cluster-client-service --url)
</code>

backup (cluster & local)
Voir https://etcd.io/docs/v3.5/op-guide/recovery/
<code bash>
ETCDCTL_API=3 etcdctl --endpoints $ENDPOINT snapshot save snapshot.db #--cacert /etc/ssl/etcd/ca.crt --cert /etc/ssl/etcd/client.crt --key /etc/ssl/etcd/client.key
</code>

Verify the snapshot:
<code bash>
ETCDCTL_API=3 etcdctl --write-out=table snapshot status snapshotdb
</code>

Restore (local)
<code bash>
ETCDCTL_API=3 etcdctl snapshot restore snapshot.db
</code>

grpc-proxy
<code bash>
etcd grpc-proxy start --endpoints=infra0.example.com,infra1.example.com,infra2.example.com --listen-addr=127.0.0.1:2379
</code>

== Tuning

IO
<code bash>
# best effort, highest priority
sudo ionice -c2 -n0 -p `pgrep etcd`
</code>

CPU
<code bash>
echo performance | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
</code>

== Diag

<code bash>
sudo chown -R etcd:etcd /var/lib/etcd
sudo systemctl start etcd
</code>

List the cluster member:
<code bash>
etcdctl --endpoints=http://${NODE1}:2379 member list
</code>

== Client API Python

https://www.dasblinkenlichten.com/python-pieces-working-with-etcd/


== Autre

=== pas de type list ?

Voir https://github.com/ake-persson/etcdtool


etcd doesn't support list's, this is handled by using the index as the key:

JSON Input:
<code javascript>
{
    "users": [
        { "username": "jblack", "first_name": "John", "last_name": "Blackbeard" },
        { "username": "ltrier", "first_name": "Lars", "last_name": "Von Trier" }
    ]
}
</code>

Result in etcd:
<code ->
users/0/username: jblack
users/0/first_name: John
users/0/last_name: Blackbeard
users/1/username: ltrier
users/1/first_name: Ludwig
users/1/last_name: Von Treimer
</code>