Configuring Resource Constraints

1. Limiting Memory Usage

Option	Values	Description
--memory	`1g`	Set memory limit for the container (e.g., 1GB)
--memory-swap	`2g`	Set total memory + swap limit (e.g., 2GB)
--memory-swappiness	`60`	Control tendency to swap (0-100, default 60)
--memory-reservation	`512m`	Soft limit for memory (e.g., 512MB)
--kernel-memory	`512m`	Limit kernel memory (deprecated in newer versions)

Example: Setting Memory Limits

docker run --memory=1g --memory-swap=2g nginx

Note: Memory limits are enforced at the container level and can be set using --memory and --memory-swap. The swap limit includes both RAM and swap space.

2. Setting Memory Reservation

Option	Values	Description
--memory-reservation	`512m`, `1g`	Memory reservation for the container (soft limit)
--memory	`1g`, `2048m`	Memory limit for the container (hard limit)

Example: Setting Memory Reservation

docker run --memory-reservation 512m --memory 1g my-app

Note: Memory reservation is a soft limit, while memory is the hard limit. The container can use more than the reserved amount if available.

3. Configuring Swap Limit

Option	Values	Description
--memory-swap	`string`	Swap limit equal to memory plus swap: '`100m`' or '`2g`'. If set to -1, the container will have unlimited swap.
--memory-swap=container	`string`	Swap limit equal to memory plus swap: '`100m`' or '`2g`'. If set to -1, the container will have unlimited swap.

Example: Setting Swap Limit for a Container

docker run --memory-swap=2g --memory=1g my-app

Note: The --memory-swap flag requires that --memory is also set. If --memory-swap is not specified, the container will use a default swap limit equal to the memory limit.

4. Limiting CPU Usage

Option	Values	Description
--cpus	`0.5`	Limits the CPU usage to 50% of a single CPU core
--cpu-period	`100000`	Specifies the CPU period in microseconds (default is 100000)
--cpu-quota	`50000`	Specifies the CPU time within the period (default is -1, no limit)
--cpu-shares	`1024`	Relative weight for CPU allocation (default is 1024)

Example: Limiting CPU Usage to 50% of One Core

docker run --cpus="0.5" ubuntu:latest

Example: Setting CPU Period and Quota

docker run --cpu-period=100000 --cpu-quota=50000 ubuntu:latest

5. Setting CPU Shares

Option	Values	Description
--cpu-shares	`1024`	Relative weight of CPU time for the container (default is 1024)
--cpu-quota	`-1`	Limit CPU usage per period (in microseconds)
--cpu-period	`100000`	Control the CPU period (in microseconds) for quota

Example: Setting CPU Shares for a Container

docker run --cpu-shares 512 my-app

Example: Using CPU Quota and Period

docker run --cpu-quota 50000 --cpu-period 100000 my-app

Note: CPU shares are relative and only effective when multiple containers are competing for CPU resources.

6. Pinning to Specific CPUs

Option	Values	Description
--cpuset-cpus	`0,1,3`	Restricts the container to run only on the specified CPUs
--cpuset-cpus	`0-3`	Restricts the container to run only on CPUs 0 through 3

Example: Running a container on specific CPUs

docker run --cpuset-cpus="0,1" my-app

Note: The --cpuset-cpus option restricts the container to specific CPU cores. This is useful for performance optimization or ensuring containers do not compete for resources on the same core.

7. Setting Block I/O Weight

Option	Values	Description
--blkio-weight	`default: 100`	Block I/O weight (relative weight) for the container. Valid range is 10-1000.

Example: Setting Block I/O Weight

docker run --blkio-weight 300 my-app

Note: The --blkio-weight option controls the relative I/O bandwidth of containers. It does not guarantee a specific amount of I/O but provides a proportional allocation based on the weight values.

8. Limiting Device Read/Write

Option	Values	Description
--device-read-bps	`<device>:<rate>`	Limit read rate (bytes per second) for a specific device
--device-write-bps	`<device>:<rate>`	Limit write rate (bytes per second) for a specific device
--device-read-iops	`<device>:<iops>`	Limit read I/O operations per second for a specific device
--device-write-iops	`<device>:<iops>`	Limit write I/O operations per second for a specific device

Example: Limiting Device Read/Write

docker run --device-read-bps /dev/sda:100mb \
           --device-write-bps /dev/sda:50mb \
           --device-read-iops /dev/sda:1000 \
           --device-write-iops /dev/sda:500 \
           ubuntu:20.04

Note: These options apply to block devices inside the container. The device path must be accessible within the container's filesystem.

9. Setting PID Limits

Option	Values	Description
--pid	`host` or `container[:pid]`	Controls PID namespace sharing. `host` shares the host's PID namespace; `container` creates a new one.
--pids-limit	`-1` or `<number>`	Sets the maximum number of processes allowed in the container. `-1` means no limit.

Example: Setting PID Limits

docker run --pids-limit 100 my-app

Note: The --pids-limit option is supported in Docker 20.10 and later.

10. Configuring Restart Policies

Policy	Description	Usage Example
no	Never restart the container if it stops or crashes.	`"restart": "no"`
on-failure[:max-retries]	Restart the container if it exits with a non-zero exit code. Optionally specify max retries.	`"restart": "on-failure:5"`
always	Always restart the container regardless of exit status.	`"restart": "always"`
unless-stopped	Restart the container unless it was stopped by the user.	`"restart": "unless-stopped"`

Example: Using restart policy in Docker Compose

services:
  web:
    image: nginx
    restart: unless-stopped

Example: Using restart policy with Docker CLI

docker run --restart=on-failure:3 my-app

11. Setting Stop Timeout

Option	Values	Description
--stop-timeout	`default: 10`	Number of seconds to wait before killing a container during stop operation

Example: Setting Stop Timeout

docker run --stop-timeout 30 my-app

Note: The stop timeout is the duration Docker waits for a container to shut down gracefully before forcibly terminating it. This setting is crucial for ensuring proper cleanup of resources and avoiding data loss.

12. Configuring OOM Killer Behavior

Option	Values	Description
--oom-kill-disable	`false`	Disables the OOM killer for the container. NEW in Docker 24.0
--oom-score-adj	`-1000` to `1000`	Adjusts the OOM score of the container process. Lower values make it less likely to be killed.

Example: Setting OOM Score Adjustment

docker run --oom-score-adj=-500 my-app

Note: The OOM killer behavior can be fine-tuned using /sys/module/oom settings on the host system.

Warning: Disabling OOM killer (--oom-kill-disable=true) can lead to system instability if the container consumes all available memory.