A while ago, I noticed that my DigitalOcean droplet memory was consistently above 90%, which I consider too high for me. 🎢
I haven't added any new services recently and even though I removed some stacks that I wasn't using, the memory impact was relatively small. I was wondering how I could improve my server's memory before I run out of it. 🤔
After searching the Internet, I came across a simple command that helped me determine which container took up too much memory: docker stats.
docker statsIf you type the command in your terminal, it will output a large table like the one below with the following statistics:
- The container ID and name
- CPU utilization percentage
- Memory usage, limits and percentage
- The amount of data the container sent and received from the network interface
- The amount of data the container has read and written on disk
- The number of processes or threads the container has started
CONTAINER ID NAME CPU % MEM USAGE / LIMIT MEM % NET I/O BLOCK I/O PIDS
4036d8b5cec0 www_benjaminrancourt_ghost.1.lozlwwfcsjrdf94y9yl5q9tbe 0.07% 137.1MiB / 256MiB 53.56% 18.4MB / 12.2MB 32.6MB / 561kB 11
2a913e0898bb phpmyadmin_phpmyadmin.1.ycvp02lpvshqiwrpg0xzk7ehm 0.00% 40.54MiB / 128MiB 31.67% 3.31MB / 27MB 7.94MB / 16.4MB 7
daee5991d4be phpmyadmin_mysql.1.txa6wbp2rj7fn9xhgnkr0dfb6 0.24% 679.5MiB / 1GiB 66.35% 122MB / 947MB 78MB / 3.27GB 46
ed326dda28b9 uptime-kuma_uptime-kuma.1.0tut77m69lyez7z8uwtqo55et 0.58% 83.83MiB / 128MiB 65.49% 1.34GB / 93.1MB 814MB / 1.91GB 12
1fcecf3bbe69 ghost_jardin_ghost.1.m9psm95qontpamrdu3ukqh2mq 0.00% 93.48MiB / 256MiB 36.52% 738kB / 73.5kB 28.4MB / 41kB 11
92f0264ea93c mealie_mealie.1.j550w0meluc8yws6zlc1xsras 0.31% 259.5MiB / 512MiB 50.69% 3.76MB / 9.9MB 34.4MB / 66.2MB 23
35a16db2c564 phpmyadmin_mariadb.1.rym9ra2c9s6m6f9gi9co3vjpt 0.02% 249.8MiB / 512MiB 48.79% 1.89MB / 2.81MB 58.4MB / 2.28GB 9
f03d490eb35c unami_umami.1.j8wyl0basbzh6h10gs4kdv18r 0.02% 118.7MiB / 256MiB 46.38% 8.98MB / 10.8MB 33.3MB / 8.19kB 25
ff362460c71c portainer_portainer.1.hoxq3gmdpk1n5ytx1w7bq6v4d 0.01% 41.09MiB / 128MiB 32.10% 8.13MB / 40.7MB 39.2MB / 37.5MB 6
e33a94ad44cc traefik_traefik.v47gxhgyo1hy62l702cdw2si0.i4vk6r11foyqxlt4lnobx6h03 0.02% 45.1MiB / 128MiB 35.24% 842MB / 1.48GB 9.29MB / 0B 10If you consider the previous output to be too verbose, you can supply an option to the format argument:
docker stats --format "table {{.Name}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.MemPerc}}"format option can be used to display only the metrics that are useful to you.NAME CPU % MEM USAGE / LIMIT MEM %
www_benjaminrancourt_ghost.1.lozlwwfcsjrdf94y9yl5q9tbe 0.06% 142.2MiB / 256MiB 55.57%
phpmyadmin_phpmyadmin.1.ycvp02lpvshqiwrpg0xzk7ehm 0.01% 40.55MiB / 128MiB 31.68%
phpmyadmin_mysql.1.txa6wbp2rj7fn9xhgnkr0dfb6 0.60% 679.6MiB / 1GiB 66.37%
uptime-kuma_uptime-kuma.1.0tut77m69lyez7z8uwtqo55et 1.15% 84.57MiB / 128MiB 66.07%
ghost_jardin_ghost.1.m9psm95qontpamrdu3ukqh2mq 0.00% 93.48MiB / 256MiB 36.52%
mealie_mealie.1.j550w0meluc8yws6zlc1xsras 0.60% 259.5MiB / 512MiB 50.69%
phpmyadmin_mariadb.1.rym9ra2c9s6m6f9gi9co3vjpt 0.03% 249.8MiB / 512MiB 48.79%
unami_umami.1.j8wyl0basbzh6h10gs4kdv18r 0.02% 118.8MiB / 256MiB 46.39%
portainer_portainer.1.hoxq3gmdpk1n5ytx1w7bq6v4d 0.00% 41.61MiB / 128MiB 32.51%
traefik_traefik.v47gxhgyo1hy62l702cdw2si0.i4vk6r11foyqxlt4lnobx6h03 0.05% 43.85MiB / 128MiB 34.26%
After seeing a table similar to the one above, I was able to identify the faulty container and take action by deleting it.
By monitoring the stats, I was also able to better adjust the Docker limits and reservations for each of my containers.
resources:
limits:
cpus: '0.750'
memory: 64M
reservations:
cpus: '0.001'
memory: 32M
The next target that I'd really like to act on is my MySQL container:
NAME CPU % MEM USAGE / LIMIT MEM % PIDS
phpmyadmin_mysql.1.txa6wbp2rj7fn9xhgnkr0dfb6 0.32% 682.2MiB / 1GiB 66.62% 47
phpmyadmin_mariadb.1.rym9ra2c9s6m6f9gi9co3vjpt 0.02% 249.9MiB / 512MiB 48.81% 10
It's crazy when you compare the MySQL and MariaDB statistics together, right? MySQL really takes too many resources to work. Unfortunately, Ghost recently choose to only support MySQL, so I'll be tied to that for a long time... 😞
What about you, have you found other ways to improve the memory usage of your containers? 🤗
