Docker-Java限制cpu和内存及浅析源码解决docker磁盘挂载失效问题

之前工作流的运行都是用的docker-java提供的api拉起的docker容器直接跑服务，但是最新线上的新业务资源消耗较大，单个容器如果不加控制，CPU和内存都会拉满，导致服务器莫名宕机事故的发生，所以Docker限制cpu使用率和内存限制就得安排上

HostConfig构建

自定义HostConfig，设置cpu和内存限制，pipeline配置了就按照配置来，如果没有就走默认配置

public void setUp() {
    this.dockerHostConfig = new HostConfig();
    Double memoryValue = this.pipeline.getMemory() != null
                            ? this.pipeline.getMemory() * 1024 * 1024 * 1024
                            : this.config.getDefaultMemoryLimitInGb() * 1024 * 1024 * 1024;
    this.dockerHostConfig.withMemory(memoryValue.longValue());

    double cpu = StringUtils.isNotBlank(this.pipeline.getCpu())
                ? Double.parseDouble(this.pipeline.getCpu())
                : this.config.getDefaultCpuCoreLimit();
    // 单个 CPU 为 1024，两个为 2048，以此类推
    this.dockerHostConfig.withCpuShares((int)(cpu * 1024));
}

CreateContainerCmd 构建

public String startContainer(String image,
                                String name,
                                List portBinds,
                                List volumeBinds,
                                List extraHosts,
                                List envs,
                                List entrypoints,
                                HostConfig hostConfig,
                                String... cmds) {
    List volumes = new ArrayList<>();
    List volumesBinds = new ArrayList<>();

    ......

    ......

    ......

    CreateContainerCmd cmd = this.client.createContainerCmd(image)
                                            .withName(name)
                                            .withVolumes(volumes)
                                            .withBinds(volumesBinds);

    if (portBinds != null && portBinds.size() > 0) {
        cmd = cmd.withPortBindings(portBindings);
    }

    if (cmds != null && cmds.length > 0) {
        cmd = cmd.withCmd(cmds);
    }

    if (extraHosts != null && extraHosts.size() > 0) {
        cmd.withExtraHosts(extraHosts);
    }

    if (envs != null) {
        cmd.withEnv(envs);
    }

    if (entrypoints != null) {
        cmd.withEntrypoint(entrypoints);
    }

    // 这一句是重点
    cmd.withHostConfig(hostConfig);

    CreateContainerResponse container = cmd.exec();
    this.client.startContainerCmd(container.getId()).exec();
    return container.getId();
}

docker inspect containerId

执行 docker inspect a436678ccb0c 结果如下

"HostConfig": {
    "Binds": [],
    "ContainerIDFile": "",
    "LogConfig": {
        "Type": "json-file",
        "Config": {
            "max-file": "3",
            "max-size": "10m"
        }
    },
    "NetworkMode": "default",
    "PortBindings": null,
    "RestartPolicy": {
        "Name": "",
        "MaximumRetryCount": 0
    }
    "CpuShares": 2048,
    "Memory": 6442450944,
    "NanoCpus": 0,
    "CgroupParent": "",
    "BlkioWeight": 0,
    "BlkioWeightDevice": null
    }

CpuShares和Memory已经是我们设置的默认值，API生效，我们再来看下执行的日志

proc "pipeline_task_4b86c7830e4c4e39a77c454589c9e7e9_1" starting 2021-09-22 17:30:15 logPath:/mnt/xx/xx/logs/2021/09/22/bfbadf65-ac41-459d-a96d-3dc9a0105c25/job.log
+ java -jar /datavolume/xxx/xx.jar  --spring.profiles.active=test
STDERR: Error: Unable to access jarfile /datavolume/xxx/xx.jar
5c494aeacb87af3a46a4fedc6e695ae888d4d2b9d7e603f24ef7fe114956c782 finished!

proc "pipeline_task_4b86c7830e4c4e39a77c454589c9e7e9_1" exited with status 1
proc "新增节点" error
start to kill all pipeline task
pipeline exit with error

执行文件没有找到，向上看Binds为空，所以挂载丢了，可以为什么了？明明 withVolumes() 和 withBinds() 两个方法逻辑都没有动，还是看下源码分析一下吧

看源码之前我们先了解一下docker的hostConfig，文件路径在：/var/lib/docker/containers/{container-id}/hostconfig.json
其实这个就是容器运行的宿主机配置，磁盘绑定，cpu、内存限制、DNS、网络以及种种配置都在这个文件中，docker-java中HostConfig对象其实就是这个json对应的model，我们自定义了HostConfig对象，问题应当是出在 cmd.withHostConfig(hostConfig); 这一句代码上

以前的绑定逻辑
之前没有限制，所以在实例化CreateContainerCmd时候没有定制HostConfig参数

CreateContainerCmd cmd = this.client.createContainerCmd(image)
                        .withName(name)
                        .withVolumes(volumes)
                        .withBinds(volumesBinds);

CreateContainerCmd withBinds

/**
     *
     * @deprecated see {@link #getHostConfig()}
     */
    @Deprecated
    default CreateContainerCmd withBinds(Bind... binds) {
        Objects.requireNonNull(binds, "binds was not specified");
        getHostConfig().setBinds(binds);
        return this;
    }

@JsonProperty("HostConfig")
private HostConfig hostConfig = new HostConfig();

我们再看下 CreateContainerCmd 的 withHostConfig() 方法，代码也是在实现类里面

@Override
public CreateContainerCmd withHostConfig(HostConfig hostConfig) {
    this.hostConfig = hostConfig;
    return this;
}

直接覆盖了对象中原来的hostConfig, 我们的withHostConfig又在最后调用的可不就把挂载丢了吗，正好CreateContainerCmd 的 withBinds 方法也被 @Deprecated 修饰了，我们就来调整一下代码

public String startContainer(String image,
                                String name,
                                List portBinds,
                                List volumeBinds,
                                List extraHosts,
                                List envs,
                                List entrypoints,
                                HostConfig hostConfig,
                                String... cmds) {
    List volumes = new ArrayList<>();
    List volumesBinds = new ArrayList<>();

    ......

    //这一行很关键
    hostConfig.withBinds(volumesBinds);

    if (portBinds != null && portBinds.size() > 0) {
        hostConfig.withPortBindings(portBindings);
    }

    if (extraHosts != null && extraHosts.size() > 0) {
        hostConfig.withExtraHosts(extraHosts.toArray(new String[extraHosts.size()]));
    }
    CreateContainerCmd cmd = this.client.createContainerCmd(image).withHostConfig(hostConfig)
        .withName(name)
        .withVolumes(volumes);

    if (cmds != null && cmds.length > 0) {
        cmd = cmd.withCmd(cmds);
    }

    if (envs != null) {
        cmd.withEnv(envs);
    }

    if (entrypoints != null) {
        cmd.withEntrypoint(entrypoints);
    }

    CreateContainerResponse container = cmd.exec();
    this.client.startContainerCmd(container.getId()).exec();
    return container.getId();
};

OK，搞定， docker stats 查看容器的cpu占用，始终不会超过200%

Original: https://www.cnblogs.com/surging-dandelion/p/15354045.html
Author: 蒲公英的狂想
Title: Docker-Java限制cpu和内存及浅析源码解决docker磁盘挂载失效问题