Master Docker Data Persistence, Networking, and Resource Limits: Practical Guide

Docker Data Persistence Methods

Docker provides three ways to mount host data into containers: volumes, bind mounts, and tmpfs.

volumes : Docker-managed storage under /var/lib/docker/volumes, recommended for persisting data.

bind mounts : Mount any host directory or file into the container.

tmpfs : Stores data in host memory, not written to disk, useful for non‑persistent data and performance.

docker volume create nginx_vol
ls /var/lib/docker/volumes/nginx_vol/

Data is stored in the _data directory.

Example 1 – Using volumes

docker run -d --name nginx-ceshi -p 888:80 --mount -v nginx-ceshi:/usr/share/nginx/html nginx
# or
docker run -d --name nginx-ceshi -p 888:80 --mount src=nginx-ceshi,dst=/usr/share/nginx/html nginx
docker inspect nginx-ceshi

After creating the container you can see the persisted data directory.

cd /var/lib/docker/volumes/nginx-ceshi/_data
echo "hello world nginx" > index.html
# Access http://<host>:888/ to verify persistence

Example 2 – Bind mounts

docker run -d -it --name=nginx-test --mount type=bind,src=/app/wwwroot,dst=/usr/share/nginx/html/ nginx
docker run -d -it --name=nginx-test -v /root/html:/usr/share/nginx/html/ nginx

Notes: -v with an absolute path creates a bind mount; -v with a name creates a volume. Bind source must exist; the container’s mount point hides existing files.

Docker Network Modes

bridge

-net=bridge – default mode, Docker creates a docker0 bridge and attaches containers.

host

-net=host – container shares the host’s network namespace, no separate network interface.

none

-net=none – container gets an isolated network namespace but no network configuration; user must configure manually.

container

-net=container:Name/ID – shares the network namespace of another container while keeping other namespaces isolated.

Example:

docker run -itd --name zd -p 99:80 busybox
docker run -itd --name nginx-zd --net container:zd nginx
curl 192.168.106.100:99   # nginx uses zd’s network

Custom networks behave like bridge but provide internal DNS for container‑to‑container name resolution.

docker network create zf-100

Docker Resource Limits

Docker can limit container resources to prevent exhausting the host and to improve isolation.

Common options:

-m, --memory            Max memory the container can use
--memory-swap           Amount of memory+swap allowed
--oom-kill-disable      Disable OOM killer
--cpus                  Number of CPUs the container can use
--cpuset-cpus           Specific CPU cores (e.g., 0-3)
--cpu-shares            Relative CPU weight

Examples:

docker run -d --name web03 --memory="500m" --memory-swap="600m" --oom-kill-disable nginx
docker stats --no-stream web03   # view memory usage

docker run -d --name web01 --cpus="1" nginx   # limit to one CPU
docker run -d --name web01 --cpus=".5" nginx   # limit to 50% CPU