bash - 增强的 docker stats 命令，包含 RAM 和 CPU 总量

Question

我只想分享我为增强 docker stats 命令而制作的一个小脚本。我不确定这种方法的准确性。

我可以假设整个 Docker 部署消耗的内存总量是每个容器消耗内存的总和吗？

请分享您的修改和/或更正。此命令记录在此处:https://docs.docker.com/engine/reference/commandline/stats/

当运行 docker stats 时，输出如下所示:

$ docker stats --all --format "table {{.MemPerc}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.Name}}"
MEM %       CPU %       MEM USAGE / LIMIT       NAME              
0.50%       1.00%       77.85MiB / 15.57GiB     ecstatic_noether  
1.50%       3.50%       233.55MiB / 15.57GiB    stoic_goodall     
0.25%       0.50%       38.92MiB / 15.57GiB     drunk_visvesvaraya

我的脚本将在末尾添加以下行:

2.25%       5.00%       350.32MiB / 15.57GiB    TOTAL

docker_stats.sh

#!/bin/bash

# This script is used to complete the output of the docker stats command.
# The docker stats command does not compute the total amount of resources (RAM or CPU)

# Get the total amount of RAM, assumes there are at least 1024*1024 KiB, therefore > 1 GiB
HOST_MEM_TOTAL=$(grep MemTotal /proc/meminfo | awk '{print $2/1024/1024}')

# Get the output of the docker stat command. Will be displayed at the end
# Without modifying the special variable IFS the ouput of the docker stats command won't have
# the new lines thus resulting in a failure when using awk to process each line
IFS=;
DOCKER_STATS_CMD=`docker stats --no-stream --format "table {{.MemPerc}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.Name}}"`

SUM_RAM=`echo $DOCKER_STATS_CMD | tail -n +2 | sed "s/%//g" | awk '{s+=$1} END {print s}'`
SUM_CPU=`echo $DOCKER_STATS_CMD | tail -n +2 | sed "s/%//g" | awk '{s+=$2} END {print s}'`
SUM_RAM_QUANTITY=`LC_NUMERIC=C printf %.2f $(echo "$SUM_RAM*$HOST_MEM_TOTAL*0.01" | bc)`

# Output the result
echo $DOCKER_STATS_CMD
echo -e "${SUM_RAM}%\t\t\t${SUM_CPU}%\t\t${SUM_RAM_QUANTITY}GiB / ${HOST_MEM_TOTAL}GiB\tTOTAL"

Answer 1

根据您在上面链接的文档，

The docker stats command returns a live data stream for running containers. To limit data to one or more specific containers, specify a list of container names or ids separated by a space. You can specify a stopped container but stopped containers do not return any data.

然后，

Note: On Linux, the Docker CLI reports memory usage by subtracting page cache usage from the total memory usage. The API does not perform such a calculation but rather provides the total memory usage and the amount from the page cache so that clients can use the data as needed.

根据您的问题，看起来您可以这样假设，但也不要忘记它也影响存在但未运行的容器。