コンテナのディスク使用率を測る方法。
ホストマシンから Docker の容量を確認してみる。
$ docker system df
TYPE TOTAL ACTIVE SIZE RECLAIMABLE
Images 1 1 141.8MB 0B (0%)
Containers 1 1 1.095kB 0B (0%)
Local Volumes 0 0 0B 0B
Build Cache 0 0 0B 0B
コンテナの中から、その容量を確認してみる。
$ docker container exec -it mynginx bash
（以下、コンテナの中）
/# df -h
Filesystem Size Used Avail Use% Mounted on
overlay 5.7G 236M 5.5G 5% /
tmpfs 64M 0 64M 0% /dev
shm 64M 0 64M 0% /dev/shm
/dev/sda1 5.7G 236M 5.5G 5% /etc/hosts
tmpfs 2.0G 0 2.0G 0% /proc/acpi
tmpfs 2.0G 0 2.0G 0% /proc/scsi
tmpfs 2.0G 0 2.0G 0% /sys/firmware
コンテナの中で、ファイルを作成してみる。
/# dd if=/dev/zero of=bigfile.txt bs=1M count=500
500+0 records in
500+0 records out
524288000 bytes (524 MB, 500 MiB) copied, 0.611897 s, 857 MB/s
コンテナの中で、使用容量が増えていることを確認する。
/# df -h
Filesystem Size Used Avail Use% Mounted on
overlay 5.7G 736M 5.0G 13% /
tmpfs 64M 0 64M 0% /dev
shm 64M 0 64M 0% /dev/shm
/dev/sda1 5.7G 736M 5.0G 13% /etc/hosts
tmpfs 2.0G 0 2.0G 0% /proc/acpi
tmpfs 2.0G 0 2.0G 0% /proc/scsi
tmpfs 2.0G 0 2.0G 0% /sys/firmware
ホストマシンから、コンテナの容量の詳細を確認してみる。
/# exit
$ docker system df -v
Images space usage:
REPOSITORY TAG IMAGE ID CREATED SIZE SHARED SIZE UNIQUE SIZE CONTAINERS
nginx latest 3f8a00f137a0 7 days ago 141.8MB 0B 141.8MB 1
Containers space usage:
CONTAINER ID IMAGE COMMAND LOCAL VOLUMES SIZE CREATED STATUS NAMES
67df4d402280 nginx "/docker-entrypoint.…" 0 524MB 18 minutes ago Up 18 minutes mynginx
Local Volumes space usage:
VOLUME NAME LINKS SIZE
Build cache usage: 0B
CACHE ID CACHE TYPE SIZE CREATED LAST USED USAGE SHARED
コンテナのログを確認する。
$ docker logs mynginx
/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
2023/02/16 10:54:55 [notice] 1#1: using the "epoll" event method
2023/02/16 10:54:55 [notice] 1#1: nginx/1.23.3
2023/02/16 10:54:55 [notice] 1#1: built by gcc 10.2.1 20210110 (Debian 10.2.1-6)
2023/02/16 10:54:55 [notice] 1#1: OS: Linux 5.15.65+
2023/02/16 10:54:55 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2023/02/16 10:54:55 [notice] 1#1: start worker processes
2023/02/16 10:54:55 [notice] 1#1: start worker process 29
2023/02/16 10:54:55 [notice] 1#1: start worker process 30
<IP_ADDR> - - [16/Feb/2023:10:56:13 +0000] "GET / HTTP/1.1" 200 615 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/109.0" "-"
2023/02/16 10:56:13 [error] 29#29: *1 open() "/usr/share/nginx/html/favicon.ico" failed (2: No such file or directory), client: <IP_ADDR>, server: localhost, request: "GET /favicon.ico HTTP/1.1", host: "<VM GLOBALIP>:8080", referrer: "http://<VM GLOBALIP>:8080/"
<IP_ADDR> - - [16/Feb/2023:10:56:13 +0000] "GET /favicon.ico HTTP/1.1" 404 153 "http://<VM GLOBALIP>:8080/" "Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/109.0" "-"
<IP_ADDR> - - [16/Feb/2023:10:57:45 +0000] "GET / HTTP/1.1" 304 0 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/109.0" "-"
その６：コンテナの自動削除につづく。