Conteneurs: Notions de base (Usage)

Cycle de vie, volumes, réseaux, ressources, bonnes pratiques

Emmanuel BRUNO

emmanuel.bruno@univ-tln.fr

Université de Toulon

LIS UMR CNRS 7020

2026-11-02

Objectifs du cours

À l’issue de ce cours, vous devez être capables de :

Manipuler des conteneurs Docker (run, stop, start, rm)
Utiliser les volumes pour la persistance
Connecter des conteneurs via des réseaux
Exposer des ports vers l’hôte
Gérer les ressources d’un conteneur (CPU / RAM / PIDs)
Comprendre et appliquer les bonnes pratiques d’usage

Rappel rapide

Un conteneur est une instance d’une image. L’image est un artefact immuable (voir le cours “Image”). Le conteneur est un processus isolé qui tourne sur le noyau de l’hôte.

Astuce

Image = template immuable
Conteneur = exécution d’un processus isolé

Les images

Une image contient tout le nécessaire pour exécuter une application (code, runtime, bibliothèques, dépendances, fichiers de configuration).
Chaque couche est en lecture seule, sauf la dernière (couche de conteneur).
Les images sont stockées dans des registres (Docker Hub, GitHub Container Registry, etc.).
Les images sont identifiées par un nom : [registre/]nom[:tag] (ex: docker.io/library/nginx:1.23).
- Si le registre n’est pas spécifié, Docker Hub est utilisé par défaut.
- Si le tag n’est pas spécifié, latest est utilisé par défaut.
- Une image peut être référencée par son digest (SHA256).
- Une image peut avoir plusieurs tags.
  - Ex: nginx:1, nginx:1.29,nginx:mainline, nginx:latest, nginx:f3524ef8b874 peuvent référencer la même image.
Une image est destinée à une plateforme spécifique (architecture CPU, OS).
- Ex: linux/amd64, linux/arm64/v8, windows/amd64.
- Il est possible de créer des images multi-plateformes (multi-arch).

Cycle de vie d’un conteneur

Exécution simple

La commande docker run crée et démarre un conteneur à partir d’une image.
Le conteneur s’arrête lorsque le processus principal se termine (--rm pour supprimer automatiquement après).
Le format général est docker run [OPTIONS] IMAGE [COMMAND] [ARG...].
Si l’image n’est pas présente localement, Docker la télécharge depuis le registre.

#| label: lst-run-alpine
#| title: "Premier conteneur Docker"
#| caption: "Exécution d’un conteneur Alpine jetable affichant un message"
#| code-fold: true
#| code-summary: "Afficher la commande Docker"
#| collapse: true
docker run --label teaching-demo=true --rm alpine:3.18 echo "Hello"

Unable to find image 'alpine:3.18' locally
3.18: Pulling from library/alpine


44cf07d57ee4: Pulling fs layer 

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44cf07d57ee4: Verifying Checksum 

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44cf07d57ee4: Extracting  3.418MB/3.418MB

44cf07d57ee4: Pull complete 
Digest: sha256:de0eb0b3f2a47ba1eb89389859a9bd88b28e82f5826b6969ad604979713c2d4f
Status: Downloaded newer image for alpine:3.18
Hello

Conteneur en arrière-plan (`--detach`, `-d`)

La commande docker run -d démarre un conteneur en arrière-plan (détaché --detach).

#| label: lst-run-nginx
#| title: "Conteneur Nginx en arrière-plan"
#| caption: "Démarrage d’un conteneur Nginx en arrière-plan"
docker rm -f my-nginx >/dev/null 2>&1 || true
docker run --label teaching-demo=true -d --name my-nginx nginx:1.23

Unable to find image 'nginx:1.23' locally
1.23: Pulling from library/nginx


f03b40093957: Pulling fs layer 

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0972072e0e8a: Verifying Checksum 

0972072e0e8a: Download complete 

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9989f7b33228: Pull complete 
Digest: sha256:f5747a42e3adcb3168049d63278d7251d91185bb5111d2563d58729a5c9179b0
Status: Downloaded newer image for nginx:1.23
b903ea7495b4f64dfb1435867e8588a2a8e8640f989a9e5e977c4c989c11e471

Liste des conteneurs (`container ls`, `ps`)

La commande docker ps (docker container ls) liste les conteneurs en cours d’exécution.
L’option -a liste tous les conteneurs (y compris arrêtés).
Chaque conteneur a un ID unique, un nom, un statut, des ports exposés, etc.

#| label: lst-docker-ps
#| title: "Liste des conteneurs en cours d’exécution"
#| caption: "Affichage des conteneurs Docker en cours d’exécution"
docker ps

CONTAINER ID   IMAGE                                     COMMAND                  CREATED         STATUS                  PORTS     NAMES
b903ea7495b4   nginx:1.23                                "/docker-entrypoint.…"   3 seconds ago   Up Less than a second   80/tcp    my-nginx
2464ef8579e7   ghcr.io/ebpro/solen:quarto-full-v1.3.42   "bash -lc 'source /h…"   5 minutes ago   Up 5 minutes                      quarto-render-41404451138

Arrêter (`stop`) / démarrer (`start`) / supprimer (`rm`)

Le cycle de vie d’un conteneur inclut les états : démarré, arrêté, supprimé.
Lorsqu’un conteneur est arrêté, il reste sur le système jusqu’à sa suppression (rm).

#| label: lst-stop-nginx
docker stop my-nginx

my-nginx

#| label: lst-docker-ps-all
docker ps -a

CONTAINER ID   IMAGE                                     COMMAND                  CREATED         STATUS                              PORTS     NAMES
b903ea7495b4   nginx:1.23                                "/docker-entrypoint.…"   4 seconds ago   Exited (0) Less than a second ago             my-nginx
2464ef8579e7   ghcr.io/ebpro/solen:quarto-full-v1.3.42   "bash -lc 'source /h…"   5 minutes ago   Up 5 minutes                                  quarto-render-41404451138

#| label: lst-start-nginx
docker start my-nginx

my-nginx

#| label: lst-rm-nginx
docker stop my-nginx

my-nginx

#| label: lst-rm-nginx
docker rm my-nginx

my-nginx

Exercice 1

Lancer un conteneur alpine, exécuter uname -a, puis le supprimer.

#| label: lst-run-alpine-uname
docker rm -f my-alpine >/dev/null 2>&1 || true
docker run --label teaching-demo=true --name my-alpine alpine:3.18 uname -a
docker rm my-alpine

Linux 9d38d6da55c2 6.8.0-142-generic #142-Ubuntu SMP PREEMPT_DYNAMIC Wed Sep  2 14:24:27 UTC 2026 x86_64 Linux
my-alpine

L’option --rm peut être utilisée avec docker run pour supprimer automatiquement le conteneur après son arrêt.

Logs, exec et monitoring

Les logs d’un conteneur sont accessibles via docker logs.
L’option -f permet de suivre les logs en temps réel.

#| label: lst-run-nginx-logs
docker rm -f my-nginx >/dev/null 2>&1 || true
docker run --label teaching-demo=true --name my-nginx -d nginx:1.23

d4aed94d312c56f4a4a3b9cc5b5944e89ac26fbadad08f303234d3328def2dc0

#| label: lst-docker-logs
docker logs my-nginx
# docker logs -f my-nginx

/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2026/11/02 07:21:10 [notice] 1#1: using the "epoll" event method
2026/11/02 07:21:10 [notice] 1#1: nginx/1.23.4
2026/11/02 07:21:10 [notice] 1#1: built by gcc 10.2.1 20210110 (Debian 10.2.1-6) 
2026/11/02 07:21:10 [notice] 1#1: OS: Linux 6.8.0-142-generic
2026/11/02 07:21:10 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2026/11/02 07:21:10 [notice] 1#1: start worker processes
2026/11/02 07:21:10 [notice] 1#1: start worker process 29
2026/11/02 07:21:10 [notice] 1#1: start worker process 30
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2026/11/02 07:21:10 [notice] 1#1: start worker process 60

Exécuter une commande dans un conteneur en cours

La commande docker exec permet d’exécuter des commandes dans un conteneur en cours d’exécution.
Lance un nouveau processus dans le conteneur
- docker exec container <cmd> → non interactif
- docker exec -it container sh→ interactif (ou un autre shell ou programme interactif)

#| label: lst-run-nginx-exec
docker exec my-nginx ls /usr/share/nginx/html

50x.html
index.html

#| label: lst-run-nginx-exec-interactive
docker stop my-nginx
docker rm my-nginx

my-nginx
my-nginx

Monitoring

La commande docker stats affiche l’utilisation des ressources (CPU, mémoire, réseau, disques) des conteneurs en cours d’exécution.
L’option --no-stream affiche une seule fois les statistiques.

#| label: lst-docker-stats
docker stats --no-stream

CONTAINER ID   NAME                        CPU %     MEM USAGE / LIMIT   MEM %     NET I/O          BLOCK I/O       PIDS
2464ef8579e7   quarto-render-41404451138   0.14%     589.2MiB / 5GiB     11.51%    2.1MB / 83.9kB   188MB / 355MB   57

Réseau

Chaque conteneur a une interface réseau virtuelle et une adresse IP.
Par défaut, les conteneurs sont connectés à un réseau bridge par défaut.
Il est possible de créer des réseaux custom pour isoler les conteneurs.
Les conteneurs sur le même réseau custom peuvent communiquer entre eux par nom (DNS interne).

Réseau par défaut (bridge)

Par défaut, Docker crée un réseau bridge nommé bridge.

#| label: lst-docker-network-ls
docker rm -f c1 >/dev/null 2>&1 || true
docker run --label teaching-demo=true -d --name c1 alpine:3.18 sleep 3600
docker rm -f c2 >/dev/null 2>&1 || true
docker run --label teaching-demo=true -d --name c2 alpine:3.18 sleep 3600

73741124e5d128e2eca70e91e6eb737f671eedc4331e806b2ad71f8a5dcbef00
07d5987fa5868b11bbd425767aba65317f0a492f235cfa7e81638aadb61b30a4

Les conteneurs ont une adresse IP dans le réseau bridge par défaut.
- La commande docker inspect permet de voir les détails d’un conteneur et permet de définir un format personnalisé (ici l’adresse IP).

#| label: lst-docker-inspect-ip
# Robustesse du rendu : si un conteneur est absent (échec transitoire de `docker run`),
# on le recrée avant l'inspect pour ne pas faire échouer tout le rendu.
for c in c1 c2; do
  docker inspect "$c" >/dev/null 2>&1 || \
    docker run --label teaching-demo=true -d --name "$c" alpine:3.18 sleep 3600
done
docker inspect -f '{{.Name}} - {{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' c1 c2

/c1 - 172.17.0.3
/c2 - 172.17.0.4

❌ Sur le réseau bridge par défaut :

les conteneurs n’ont pas de DNS interne
ils ne peuvent pas se résoudre par nom

#| label: lst-docker-ping-fail
docker exec c1 ping -c 1 c2

ping: bad address 'c2'

: 1

Réseau custom (bonne pratique)

Créer un réseau custom avec docker network create.
Lancer des conteneurs (un serveur web, une base de données) sur ce réseau avec --network.

#| label: lst-docker-network-create
docker network inspect app-net >/dev/null 2>&1 || docker network create app-net

docker rm -f web >/dev/null 2>&1 || true
docker run --label teaching-demo=true --detach --name web \
  --network app-net \
  nginx:1.23

# Robustesse du rendu : on attend que le conteneur web soit réellement en cours
# d'exécution (limite 30 s) avant les tests DNS/HTTP suivants, pour éviter les
# échecs transitoires de résolution (`curl: (6) Could not resolve host: web`).
timeout 30 sh -c 'until [ "$(docker inspect -f "{{.State.Running}}" web 2>/dev/null)" = "true" ]; do sleep 1; done'

docker rm -f db >/dev/null 2>&1 || true
docker run --label teaching-demo=true --detach --name db  \
  --network app-net \
  redis:7.0.9

94e08f51b0eca9f747a91238985e5e61461407141032c052ef168b31929bcce1
3418cc892be63a6ddcecb1e719bd21c5a24e6d208f37bafd281a4b90f133ff6a
Unable to find image 'redis:7.0.9' locally
7.0.9: Pulling from library/redis


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b483de716a47: Pull complete 
Digest: sha256:e50c7e23f79ae81351beacb20e004720d4bed657415e68c2b1a2b5557c075ce0
Status: Downloaded newer image for redis:7.0.9
df2f72ac34d8d2845a3006496d25cfbe45ea334635ca516f8dada6bdc23a29ef

Vérifier le réseau (Avancé)

#| label: lst-docker-network-inspect
docker network inspect app-net

[
    {
        "Name": "app-net",
        "Id": "94e08f51b0eca9f747a91238985e5e61461407141032c052ef168b31929bcce1",
        "Created": "2026-11-02T07:21:39.141541337Z",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv4": true,
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": {},
            "Config": [
                {
                    "Subnet": "172.18.0.0/16",
                    "Gateway": "172.18.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "3418cc892be63a6ddcecb1e719bd21c5a24e6d208f37bafd281a4b90f133ff6a": {
                "Name": "web",
                "EndpointID": "6a2fa354e404cd7fd0383c5f705d038af6dd09e400da52ba38be4daaaadb9665",
                "MacAddress": "5a:21:8f:e6:db:56",
                "IPv4Address": "172.18.0.2/16",
                "IPv6Address": ""
            },
            "df2f72ac34d8d2845a3006496d25cfbe45ea334635ca516f8dada6bdc23a29ef": {
                "Name": "db",
                "EndpointID": "fa4486065ca2050769209b7c6edeb9b06b5785852cd46487d3fad0f00b975e3f",
                "MacAddress": "56:32:ac:93:98:ff",
                "IPv4Address": "172.18.0.3/16",
                "IPv6Address": ""
            }
        },
        "Options": {},
        "Labels": {}
    }
]

Communication conteneur → conteneur

#| label: lst-docker-ping-success
docker run --label teaching-demo=true --rm --network app-net curlimages/curl:7.88.1 \
  --retry 5 --retry-connrefused --retry-delay 1 http://web

Unable to find image 'curlimages/curl:7.88.1' locally
7.88.1: Pulling from curlimages/curl


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d4c655b444ee: Pull complete 
Digest: sha256:48318407b8d98e8c7d5bd4741c88e8e1a5442de660b47f63ba656e5c910bc3da
Status: Downloaded newer image for curlimages/curl:7.88.1
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed

  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

100   615  100   615    0     0   169k      0 --:--:-- --:--:-- --:--:--  200k

Exercice 2 (Max 10 min)

Créer un réseau mynet, lancer deux conteneurs alpine nommés a1 et a2 sur ce réseau, puis vérifier qu’ils se ping par nom en exécutant une commande dans un conteneur en mode non-interactif.

Port mapping

Chaque conteneur a son propre espace réseau isolé.
Ils peuvent donc utiliser les mêmes ports en interne sans conflit.
- Ex: plusieurs conteneurs postgres peuvent écouter sur leur port 5432.
Pour exposer un service d’un conteneur vers l’hôte, utiliser --publish hôte:conteneur.
Cela mappe un port de l’hôte vers un port du conteneur.
- Ex: --publish 8080:80 mappe le port 8080 de l’hôte vers le port 80 du conteneur.
- Attention aux conflits de ports sur l’hôte.
- Attention si docker tourne dans une VM (WSL, Docker Desktop) : le port est exposé sur la VM, pas directement sur l’hôte.
- Le port mapping est une règle de NAT entre l’hôte et le réseau bridge Docker.

#| label: lst-docker-port-mapping
docker rm -f web-port-1 >/dev/null 2>&1 || true
docker run --label teaching-demo=true --detach --name web-port-1 --publish 8080:80 nginx:1.28

docker rm -f web-port-2 >/dev/null 2>&1 || true
docker run --label teaching-demo=true --detach --name web-port-2 --publish 8081:80 nginx:1.23

Unable to find image 'nginx:1.28' locally
1.28: Pulling from library/nginx


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Digest: sha256:146adea4768b83c607d0bdfa4188464e3da6e0a3ad4475db1d1d8f64f27c29cc
Status: Downloaded newer image for nginx:1.28
31fb69eefa00448bd7313c85bbf61d8e694c9b0f3297045f52992a9629e0662a
1bbfca16c8d3ac67e9bb4b50020d3748687d3c24264b440ff2769b872697c4fb

Tester depuis l’hôte

Il est possible de tester l’accès au service exposé depuis l’hôte avec curl ou un navigateur.
Avec l’adresse http://localhost:8080 si Docker est natif.
Avec l’adresse IP de la VM si Docker tourne dans une VM (ex: WSL, Docker Desktop).
A moins que Docker soit configuré pour exposer les ports vers l’hôte directement.

curl --max-time 30 -I http://localhost:8080

curl --max-time 30 -I http://localhost:8081

#| label: lst-docker-port-mapping-curl
curl --max-time 30 -I http://dind:8080

curl --max-time 30 -I http://dind:8081

HTTP/1.1 200 OK


Server: nginx/1.28.3


Date: Mon, 02 Nov 2026 07:22:10 GMT


Content-Type: text/html


Content-Length: 615


Last-Modified: Tue, 24 Mar 2026 18:33:23 GMT


Connection: keep-alive


ETag: "69c2d8f3-267"


Accept-Ranges: bytes





HTTP/1.1 200 OK


Server: nginx/1.23.4


Date: Mon, 02 Nov 2026 07:22:10 GMT


Content-Type: text/html


Content-Length: 615


Last-Modified: Tue, 28 Mar 2023 15:01:54 GMT


Connection: keep-alive


ETag: "64230162-267"


Accept-Ranges: bytes

Accès conteneur -> hôte

Il est possible d’accéder à un service exposé sur l’hôte depuis un conteneur.
Utiliser host.docker.internal comme nom d’hôte.
ATTENTION : host.docker.internal fonctionne nativement sur Docker Desktop (Windows/Mac) et Docker sous Linux (depuis Docker 20.10) mais n’est standardisé que sur Docker Desktop.

docker run --label teaching-demo=true --rm \
    curlimages/curl:7.88.1 http://host.docker.internal:8080

Volumes : persistance

Les données dans un conteneur sont éphémères : elles disparaissent à l’arrêt/suppression du conteneur.
Pour persister les données, utiliser des volumes.
Un volume est un espace de stockage géré par Docker, indépendant du cycle de vie des conteneurs.
Les volumes peuvent être montés dans un conteneur avec --volume volume:chemin_dans_conteneur.
Il existe deux types de volumes :
- Bind mount : mappe un répertoire de l’hôte vers un répertoire du conteneur.
- Volume nommé : volume géré par Docker, stocké dans l’espace de stockage Docker.

Astuce

bind mount = couplage fort hôte ↔︎ conteneur
volume nommé = abstraction portable

Bind mount (risky, dev)

montage avec --volume /chemin/host:/chemin/conteneur

#| output: true
#| echo: true

#| label: lst-bind-mount-nginx
echo "hello" > ${TP_DIR}/www/index.html

docker run --label teaching-demo=true --rm -v ${TP_DIR}/www:/usr/share/nginx/html \
  -p :80 nginx:1.23

- Utile en développement pour monter du code source.
- Permet d’éditer les fichiers sur l’hôte et de les voir dans le conteneur.
- Dangers :
  - les permissions peuvent poser problème selon l’OS hôte
  - les performances peuvent être dégradées (ex: Docker Desktop sur Windows/Mac)
  - le conteneur ne peut pas être déplacé facilement (dépendance à l’hôte)

Volume nommé (better, prod)

montage avec --volume nom_volume:chemin/conteneur

#| label: lst-named-volume-postgres
IMAGE="postgres:15.2"
VOLUME="pgdata"
PW="secret"

docker volume create "$VOLUME"

# Initialisation de la base et création d'une table
docker rm -f db >/dev/null 2>&1 || true
docker run --label teaching-demo=true -d --name db \
  -v "$VOLUME":/var/lib/postgresql/data \
  -e POSTGRES_PASSWORD="$PW" \
  "$IMAGE"

# Attendre que la base soit prête
timeout 60 sh -c 'until docker exec db pg_isready -U postgres >/dev/null 2>&1; do echo -n '.'; sleep 1; done' || (echo "Postgres not ready after 60s" >&2; exit 1)

# Créer une table et insérer des données depuis le conteneur de la base
docker exec db psql -U postgres -c "CREATE TABLE test (id SERIAL PRIMARY KEY, name VARCHAR(50));"
docker exec db psql -U postgres -c "INSERT INTO test (name) VALUES ('Alice'), ('Bob');"

# Arrêter et supprimer le conteneur mais conserver le volume
docker stop db && docker rm db

pgdata
b49ca38a6816f6ce67f6fae1970df34e45838ede044e3ad5757de872310f96e3
.
psql: error: connection to server on socket "/var/run/postgresql/.s.PGSQL.5432" failed: No such file or directory
    Is the server running locally and accepting connections on that socket?
ERROR:  relation "test" does not exist
LINE 1: INSERT INTO test (name) VALUES ('Alice'), ('Bob');
                    ^
db
db

#| label: lst-verify-named-volume
# Redémarrer un nouveau conteneur avec le même volume
docker rm -f db2 >/dev/null 2>&1 || true
docker run --label teaching-demo=true -d --name db2 \
  -v "$VOLUME":/var/lib/postgresql/data \
  -e POSTGRES_PASSWORD="$PW" \
  "$IMAGE"

# Attendre que la base soit prête
timeout 60 sh -c 'until docker exec db2 pg_isready -U postgres >/dev/null 2>&1; do echo -n '.'; sleep 1; done' || (echo "Postgres not ready after 60s" >&2; exit 1)

# Vérifier que les données persistent
docker exec db2 psql -U postgres -c "SELECT * FROM test;"

# Nettoyage
docker stop db2 && docker rm db2
docker volume rm "$VOLUME"

4794b3a7ebbb48e16cefb9d9a47d6011a2baf531c4c333e7ddee949c2f5e08d8
ERROR:  relation "test" does not exist
LINE 1: SELECT * FROM test;
                      ^
db2
db2
pgdata

Exercice de persistance

lancer MySQL sans volume → perdre les données
relancer avec volume → conserver les données

Hint: l’image officielle MySQL stocke les données dans /var/lib/mysql. Voir la page Docker Hub : https://hub.docker.com/_/mysql

Exercice 3 (10 min)

Démarrer MySQL au premier plan, observer l’initialisation (création de la base), arrêter avec Ctrl‑C, puis relancer le même volume et constater qu’il n’y a plus d’initialisation.

Consignes :

Lisez la page Docker Hub de MySQL pour comprendre
- les variables d’environnement essentielles (notamment MYSQL_ROOT_PASSWORD, MYSQL_DATABASE) : https://hub.docker.com/_/mysql
- le chemmin de stockage des données dans le conteneur (/var/lib/mysql)
Créez un volume nommé mysql-data pour stocker les données persistantes.
Démarrez MySQL en mode attaché (sans --detach

#| label: lst-mysql-persistence

# create a named volume for MySQL data (one-time)
docker volume create mysql-data

export MYSQL_ROOT_PASSWORD=secretpw
export MYSQL_DATABASE=demo

# Run MySQL in the foreground so you see initialization logs
docker rm -f mysql-db >/dev/null 2>&1 || true
docker run --label teaching-demo=true --name mysql-db --detach\
  --env MYSQL_ROOT_PASSWORD=${MYSQL_ROOT_PASSWORD} \
  --env MYSQL_DATABASE=${MYSQL_DATABASE} \
  --volume mysql-data:/var/lib/mysql \
  mysql:8.0

# Wait for MySQL to be ready
timeout 60 sh -c 'until docker exec mysql-db mysqladmin ping -h "localhost" --silent >/dev/null 2>&1; do echo -n "."; sleep 1; done' || (echo "MySQL not ready after 60s" >&2; exit 1)

# Stop and remove the container to simulate a restart
docker stop mysql-db && docker rm mysql-db

# Start a new container with the same volume to see data persistence.
docker rm -f mysql-db >/dev/null 2>&1 || true
docker run --label teaching-demo=true --name mysql-db --detach\
  --env MYSQL_ROOT_PASSWORD=${MYSQL_ROOT_PASSWORD} \
  --env MYSQL_DATABASE=${MYSQL_DATABASE} \
  --volume mysql-data:/var/lib/mysql \
  mysql:8.0

# Wait for MySQL to be ready again
timeout 60 sh -c 'until docker exec mysql-db mysqladmin ping -h "localhost" --silent >/dev/null 2>&1; do echo -n "."; sleep 1; done' || (echo "MySQL not ready after 60s" >&2; exit 1)

# Check the logs to confirm no re-initialization
docker logs mysql-db|head -n 20

mysql-data
Unable to find image 'mysql:8.0' locally
8.0: Pulling from library/mysql


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7534d1db9f8d: Downloading     316B/316B

7534d1db9f8d: Verifying Checksum 

7534d1db9f8d: Download complete 

49ec2dab01d9: Downloading  539.3kB/129.4MB

edf85873f64e: Extracting  5.898MB/47.31MB

a63160a5eda1: Downloading  21.33MB/49.93MB

49ec2dab01d9: Downloading   6.43MB/129.4MB

a63160a5eda1: Downloading  27.43MB/49.93MB

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ab24264a27e9: Downloading  3.198kB/5.327kB

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ab24264a27e9: Download complete 

49ec2dab01d9: Downloading  17.66MB/129.4MB

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a63160a5eda1: Downloading   38.6MB/49.93MB

49ec2dab01d9: Downloading  24.58MB/129.4MB

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a63160a5eda1: Downloading  44.69MB/49.93MB

49ec2dab01d9: Downloading  31.52MB/129.4MB

a63160a5eda1: Verifying Checksum 

a63160a5eda1: Download complete 

edf85873f64e: Extracting  12.29MB/47.31MB

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edf85873f64e: Extracting  33.42MB/47.31MB

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edf85873f64e: Extracting  41.29MB/47.31MB

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96d30d9fbee8: Downloading     120B/120B

96d30d9fbee8: Verifying Checksum 

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edf85873f64e: Extracting  42.76MB/47.31MB

49ec2dab01d9: Downloading    125MB/129.4MB

49ec2dab01d9: Verifying Checksum 

49ec2dab01d9: Download complete 

edf85873f64e: Extracting  44.24MB/47.31MB

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edf85873f64e: Extracting  47.31MB/47.31MB

edf85873f64e: Pull complete 

6ef6c7b50a93: Extracting     884B/884B

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6ef6c7b50a93: Pull complete 

e3e5d1ac74c1: Extracting  32.77kB/783.6kB

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e3e5d1ac74c1: Pull complete 

0d74d296605b: Extracting  65.54kB/6.173MB

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297d04cfe470: Extracting  2.607kB/2.607kB

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4c8a3e0d4e4b: Extracting     335B/335B

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a63160a5eda1: Extracting  524.3kB/49.93MB

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a63160a5eda1: Extracting  48.76MB/49.93MB

a63160a5eda1: Extracting  49.93MB/49.93MB

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7534d1db9f8d: Extracting     316B/316B

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49ec2dab01d9: Extracting  557.1kB/129.4MB

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49ec2dab01d9: Pull complete 

ab24264a27e9: Extracting  5.327kB/5.327kB

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ab24264a27e9: Pull complete 

96d30d9fbee8: Extracting     120B/120B

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96d30d9fbee8: Pull complete 
Digest: sha256:7dcddc01f13bab2f15cde676d44d01f61fc9f99fe7785e86196dfc07d358ae2b
Status: Downloaded newer image for mysql:8.0
4fbd628f70d17e5bace319c5dcf651134c2aed1a0b64ac26f160ba4952a87913
..............................
mysql-db
mysql-db
0d1ff2f05ddb78d8b945c19b44163acf1baeb47a0087a79bce5e18b2261bd685
......
2026-11-02 07:23:54+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.46-1.el9 started.
2026-11-02T07:23:55.534139Z 0 [Warning] [MY-011068] [Server] The syntax '--skip-host-cache' is deprecated and will be removed in a future release. Please use SET GLOBAL host_cache_size=0 instead.
2026-11-02 07:23:54+00:00 [Note] [Entrypoint]: Switching to dedicated user 'mysql'
2026-11-02 07:23:55+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.46-1.el9 started.
'/var/lib/mysql/mysql.sock' -> '/var/run/mysqld/mysqld.sock'
2026-11-02T07:23:55.536259Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.46) starting as process 1
2026-11-02T07:23:55.546212Z 1 [System] [MY-013576] [InnoDB] InnoDB initialization has started.
2026-11-02T07:23:59.917997Z 1 [System] [MY-013577] [InnoDB] InnoDB initialization has ended.
2026-11-02T07:24:00.403044Z 0 [System] [MY-010229] [Server] Starting XA crash recovery...
2026-11-02T07:24:00.428537Z 0 [System] [MY-010232] [Server] XA crash recovery finished.
2026-11-02T07:24:01.043193Z 0 [Warning] [MY-010068] [Server] CA certificate ca.pem is self signed.
2026-11-02T07:24:01.043281Z 0 [System] [MY-013602] [Server] Channel mysql_main configured to support TLS. Encrypted connections are now supported for this channel.
2026-11-02T07:24:01.103027Z 0 [Warning] [MY-011810] [Server] Insecure configuration for --pid-file: Location '/var/run/mysqld' in the path is accessible to all OS users. Consider choosing a different directory.
2026-11-02T07:24:01.271077Z 0 [System] [MY-011323] [Server] X Plugin ready for connections. Bind-address: '::' port: 33060, socket: /var/run/mysqld/mysqlx.sock
2026-11-02T07:24:01.271209Z 0 [System] [MY-010931] [Server] /usr/sbin/mysqld: ready for connections. Version: '8.0.46'  socket: '/var/run/mysqld/mysqld.sock'  port: 3306  MySQL Community Server - GPL.

Gestion des ressources (Avancé)

Docker permet de limiter les ressources utilisées par un conteneur.
Cela inclut la mémoire, le CPU, et le nombre de PIDs.

Limiter CPU / mémoire / PIDs

#| label: lst-limit-cpu-mem

docker rm -f cpu-test >/dev/null 2>&1 || true
docker run --label teaching-demo=true --detach --name cpu-test \
  --memory="512m" \
  --cpus="0.5" \
  python:3.11-slim \
  python -c "while True: pass"

Unable to find image 'python:3.11-slim' locally
3.11-slim: Pulling from library/python


6fc242d221a6: Already exists 

ee5aaeba9945: Already exists 

24ff04c92107: Already exists 

361db8171547: Already exists 
Digest: sha256:673719e071ecf27434fd2635bbd8d00f49f4fdd81f243143438a42ced8bedf60
Status: Downloaded newer image for python:3.11-slim
0fc78f891cd66f1b61d104839dc1122f8989ae616f906c5f202e4eb2ddeea3a2

#| label: lst-monitor-cpu-mem

docker stats --no-stream cpu-test

CONTAINER ID   NAME       CPU %     MEM USAGE / LIMIT   MEM %     NET I/O      BLOCK I/O   PIDS
0fc78f891cd6   cpu-test   50.62%    3.914MiB / 512MiB   0.76%     266B / 84B   0B / 0B     1

Pensez à arrêter et supprimer le conteneur après le test :

#| label: lst-cleanup-cpu-test

docker stop cpu-test
docker rm cpu-test

cpu-test
cpu-test

Modifier les limites d’un conteneur existant

Il est possible de modifier les limites d’un conteneur en cours d’exécution avec docker update.

docker update --memory="1g" --cpus="1" cpu-test

Bonnes pratiques d’usage

Nettoyage régulier

docker container prune
docker image prune
docker volume prune
docker network prune
docker system prune --all

# NETTOYAGE COMPLET (ATTENTION : SUPPRIME TOUT)
# Y COMPRIS LES DONNESS DANS DES VOLUMES !
docker system prune --all --volumes --force # RISQUE

Éviter latest en production
- Utiliser des tags de version stables.
Ne pas stocker de secrets dans l’environnement
- Préférer --secret (ou mécanismes externes).
Logs sur stdout/stderr
- Les conteneurs doivent produire des logs vers la sortie standard.

Atelier final

Déployer une application simple composée de deux conteneurs :
- une application Java accédant à une base de données via JDBC
- une base de données PostgreSQL
Contraintes :
- chaque composant doit être dans son propre conteneur
- les deux conteneurs doivent communiquer via un réseau Docker personnalisé
- les données de la base doivent être persistées dans un volume Docker
- l’application Java doit se connecter à la base par le nom du conteneur, pas par localhost
Objectif :
- vérifier la communication entre conteneurs, l’usage des réseaux et la persistance des données.

Conclusion

A Retenir

Un conteneur est une instance d’une image, exécutant un processus isolé.
Le cycle de vie d’un conteneur inclut les états : démarré, arrêté, supprimé.
Les conteneurs peuvent être connectés via des réseaux custom pour la communication.
Les volumes permettent de persister les données indépendamment du cycle de vie des conteneurs.
Il est possible de limiter les ressources (CPU, mémoire) utilisées par un conteneur.
Appliquer les bonnes pratiques d’usage pour une gestion efficace des conteneurs.
Gérer les conteneurs manuellement n’est pas viable en production : il faut automatiser
- Outils d’Orchestration : docker compose, Kubernetes, …

Conteneurs: Notions de base (Usage)

Objectifs du cours

Rappel rapide

Les images

Cycle de vie d’un conteneur

Conteneur en arrière-plan (--detach, -d)

Liste des conteneurs (container ls, ps)

Arrêter (stop) / démarrer (start) / supprimer (rm)

Exercice 1

Logs, exec et monitoring

Exécuter une commande dans un conteneur en cours

Monitoring

Réseau

Réseau par défaut (bridge)

Réseau custom (bonne pratique)

Vérifier le réseau (Avancé)

Communication conteneur → conteneur

Exercice 2 (Max 10 min)

Port mapping

Tester depuis l’hôte

Accès conteneur -> hôte

Volumes : persistance

Bind mount (risky, dev)

Volume nommé (better, prod)

Exercice de persistance

Gestion des ressources (Avancé)

Modifier les limites d’un conteneur existant

Bonnes pratiques d’usage

Atelier final

Conclusion

Conteneur en arrière-plan (`--detach`, `-d`)

Liste des conteneurs (`container ls`, `ps`)

Arrêter (`stop`) / démarrer (`start`) / supprimer (`rm`)