这里有很多答案，但没有一个符合我的需要。我想知道提问者第一个问题的确切答案。如何知道hub.docker.com上的图像何时更新?

下面的脚本可以每天运行。在第一次运行时，它从HUB注册中心获得标记的基线和更新日期，并将它们保存在本地。从那时起，每次运行它都会检查注册表中的新标记和更新日期。因为每当有新图像存在时，它都会改变，所以它会告诉我们基本图像是否发生了变化。以下是剧本:

#!/bin/bash

DATAPATH='/data/docker/updater/data'

if [ ! -d "${DATAPATH}" ]; then
        mkdir "${DATAPATH}";
fi
IMAGES=$(docker ps --format "{{.Image}}")
for IMAGE in $IMAGES; do
        ORIGIMAGE=${IMAGE}
        if [[ "$IMAGE" != *\/* ]]; then
                IMAGE=library/${IMAGE}
        fi
        IMAGE=${IMAGE%%:*}
        echo "Checking ${IMAGE}"
        PARSED=${IMAGE//\//.}
        if [ ! -f "${DATAPATH}/${PARSED}" ]; then
                # File doesn't exist yet, make baseline
                echo "Setting baseline for ${IMAGE}"
                curl -s "https://registry.hub.docker.com/v2/repositories/${IMAGE}/tags/" > "${DATAPATH}/${PARSED}"
        else
                # File does exist, do a compare
                NEW=$(curl -s "https://registry.hub.docker.com/v2/repositories/${IMAGE}/tags/")
                OLD=$(cat "${DATAPATH}/${PARSED}")
                if [[ "${VAR1}" == "${VAR2}" ]]; then
                        echo "Image ${IMAGE} is up to date";
                else
                        echo ${NEW} > "${DATAPATH}/${PARSED}"
                        echo "Image ${IMAGE} needs to be updated";
                        H=`hostname`
                        ssh -i /data/keys/<KEYFILE> <USER>@<REMOTEHOST>.com "{ echo \"MAIL FROM: root@${H}\"; echo \"RCPT TO: <USER>@<EMAILHOST>.com\"; echo \"DATA\"; echo \"Subject: ${H} - ${IMAGE} needs update\"; echo \"\"; echo -e \"\n${IMAGE} needs update.\n\ndocker pull ${ORIGIMAGE}\"; echo \"\"; echo \".\"; echo \"quit\"; sleep 1; } | telnet <SMTPHOST> 25"
                fi

        fi
done;

您可能需要更改顶部的DATAPATH变量，并更改末尾的电子邮件通知命令以满足您的需要。对我来说，我把它SSH到我的SMTP所在的另一个网络上的服务器上。但是您也可以轻松地使用邮件命令。

现在，您还需要检查容器本身中是否有更新的包。这实际上可能比在容器工作后“拉”更有效。以下是实现这一目标的脚本:

#!/bin/bash


function needsUpdates() {
        RESULT=$(docker exec ${1} bash -c ' \
                if [[ -f /etc/apt/sources.list ]]; then \
                grep security /etc/apt/sources.list > /tmp/security.list; \
                apt-get update > /dev/null; \
                apt-get upgrade -oDir::Etc::Sourcelist=/tmp/security.list -s; \
                fi; \
                ')
        RESULT=$(echo $RESULT)
        GOODRESULT="Reading package lists... Building dependency tree... Reading state information... Calculating upgrade... 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded."
        if [[ "${RESULT}" != "" ]] && [[ "${RESULT}" != "${GOODRESULT}" ]]; then
                return 0
        else
                return 1
        fi
}

function sendEmail() {
        echo "Container ${1} needs security updates";
        H=`hostname`
        ssh -i /data/keys/<KEYFILE> <USRER>@<REMOTEHOST>.com "{ echo \"MAIL FROM: root@${H}\"; echo \"RCPT TO: <USER>@<EMAILHOST>.com\"; echo \"DATA\"; echo \"Subject: ${H} - ${1} container needs security update\"; echo \"\"; echo -e \"\n${1} container needs update.\n\n\"; echo -e \"docker exec ${1} bash -c 'grep security /etc/apt/sources.list > /tmp/security.list; apt-get update > /dev/null; apt-get upgrade -oDir::Etc::Sourcelist=/tmp/security.list -s'\n\n\"; echo \"Remove the -s to run the update\"; echo \"\"; echo \".\"; echo \"quit\"; sleep 1; } | telnet <SMTPHOST> 25"
}

CONTAINERS=$(docker ps --format "{{.Names}}")
for CONTAINER in $CONTAINERS; do
        echo "Checking ${CONTAINER}"
        if needsUpdates $CONTAINER; then
                sendEmail $CONTAINER
        fi
done

以上答案也是正确的

有两种方法

使用的人 每隔一分钟运行脚本以获取新的docker映像

我只是分享脚本，可能会对你有帮助! 你可以用cronjob，我在OSX上成功尝试过

#!/bin/bash
##You can use below commented line for setting cron tab for running cron job and to store its O/P in one .txt file  
#* * * * * /usr/bin/sudo -u admin -i bash -c /Users/Swapnil/Documents/checkimg.sh > /Users/Swapnil/Documents/cron_output.log 2>&1
# Example for the Docker Hub V2 API
# Returns all images and tags associated with a Docker Hub organization account.
# Requires 'jq': https://stedolan.github.io/jq/

# set username, password, and organization
# Filepath where your docker-compose file is present
FILEPATH="/Users/Swapnil/Documents/lamp-alpine"
# Your Docker hub user name
UNAME="ur username"
# Your Docker hub user password
UPASS="ur pwd"
# e.g organisation_name/image_name:image_tag
ORG="ur org name"
IMGNAME="ur img name"
IMGTAG="ur img tag"
# Container name
CONTNAME="ur container name"
# Expected built mins
BUILDMINS="5"
#Generally cronjob frequency
CHECKTIME="5"
NETWORKNAME="${IMGNAME}_private-network"
#After Image pulling, need to bring up all docker services?
DO_DOCKER_COMPOSE_UP=true
# -------
echo "Eecuting Script @ date and time in YmdHMS: $(date +%Y%m%d%H%M%S)"
set -e
PIDFILE=/Users/Swapnil/Documents/$IMGNAME/forever.pid
if [ -f $PIDFILE ]
then
  PID=$(cat $PIDFILE)
  ps -p $PID > /dev/null 2>&1
  if [ $? -eq 0 ]
  then
    echo "Process already running"
    exit 1
  else
    ## Process not found assume not running
    echo $$
    echo $$ > $PIDFILE
    if [ $? -ne 0 ]
    then
      echo "Could not create PID file"
      exit 1
    fi
  fi
else
  echo $$ > $PIDFILE
  if [ $? -ne 0 ]
  then
    echo "Could not create PID file"
    exit 1
  fi
fi

# Check Docker is running or not; If not runing then exit
if docker info|grep Containers ; then
    echo "Docker is running"
else
    echo "Docker is not running"
    rm $PIDFILE
    exit 1
fi

# Check Container is running or not; and set variable
CONT_INFO=$(docker ps -f "name=$CONTNAME" --format "{{.Names}}")
if [ "$CONT_INFO" = "$CONTNAME" ]; then
    echo "Container is running"
    IS_CONTAINER_RUNNING=true
else
    echo "Container is not running"
    IS_CONTAINER_RUNNING=false
fi


# get token
echo "Retrieving token ..."
TOKEN=$(curl -s -H "Content-Type: application/json" -X POST -d '{"username": "'${UNAME}'", "password": "'${UPASS}'"}' https://hub.docker.com/v2/users/login/ | jq -r .token)

# get list of repositories
echo "Retrieving repository list ..."
REPO_LIST=$(curl -s -H "Authorization: JWT ${TOKEN}" https://hub.docker.com/v2/repositories/${ORG}/?page_size=100 | jq -r '.results|.[]|.name')

# output images & tags
echo "Images and tags for organization: ${ORG}"
echo
for i in ${REPO_LIST}
do
  echo "${i}:"
  # tags
  IMAGE_TAGS=$(curl -s -H "Authorization: JWT ${TOKEN}" https://hub.docker.com/v2/repositories/${ORG}/${i}/tags/?page_size=100 | jq -r '.results|.[]|.name')
  for j in ${IMAGE_TAGS}
  do
    echo "  - ${j}"
  done
  #echo
done

# Check Perticular image is the latest or not
#imm=$(curl -s -H "Authorization: JWT ${TOKEN}" https://hub.docker.com/v2/repositories/${ORG}/${IMGNAME}/tags/?page_size=100)
echo "-----------------"
echo "Last built date details about Image ${IMGNAME} : ${IMGTAG} for organization: ${ORG}"
IMAGE_UPDATED_DATE=$(curl -s -H "Authorization: JWT ${TOKEN}" https://hub.docker.com/v2/repositories/${ORG}/${IMGNAME}/tags/?page_size=100 | jq -r '.results|.[]|select(.name | contains("'${IMGTAG}'")).last_updated')
echo "On Docker Hub IMAGE_UPDATED_DATE---$IMAGE_UPDATED_DATE"
echo "-----------------"

IMAGE_CREATED_DATE=$(docker image inspect ${ORG}/${IMGNAME}:${IMGTAG} | jq -r '.[]|.Created')
echo "Locally IMAGE_CREATED_DATE---$IMAGE_CREATED_DATE"

updatedDate=$(date -jf '%Y-%m-%dT%H:%M' "${IMAGE_UPDATED_DATE:0:16}" +%Y%m%d%H%M%S) 
createdDate=$(date -jf '%Y-%m-%dT%H:%M' "${IMAGE_CREATED_DATE:0:16}" +%Y%m%d%H%M%S)
currentDate=$(date +%Y%m%d%H%M%S)

start_date=$(date -jf "%Y%m%d%H%M%S" "$currentDate" "+%s")
end_date=$(date -jf "%Y%m%d%H%M%S" "$updatedDate" "+%s")
updiffMins=$(( ($start_date - $end_date) / (60) ))
if [[ "$updiffMins" -lt $(($CHECKTIME+1)) ]]; then
        if [ ! -d "${FILEPATH}" ]; then
            mkdir "${FILEPATH}";
        fi
        cd "${FILEPATH}"
        pwd
        echo "updatedDate---$updatedDate" > "ScriptOutput_${currentDate}.txt"
        echo "createdDate---$createdDate" >> "ScriptOutput_${currentDate}.txt"
        echo "currentDate---$currentDate" >> "ScriptOutput_${currentDate}.txt"
        echo "Found after regular checking time -> Docker hub's latest updated image is new; Diff ${updiffMins} mins" >> "ScriptOutput_${currentDate}.txt"
        echo "Script is checking for latest updates after every ${CHECKTIME} mins" >> "ScriptOutput_${currentDate}.txt"
        echo "Fetching all new"
        echo "---------------------------"
        if $IS_CONTAINER_RUNNING ; then
            echo "Container is running"         
        else
            docker-compose down
            echo "Container stopped and removed; Network removed" >> "ScriptOutput_${currentDate}.txt"
        fi
        echo "Image_Created_Date=$currentDate" > ".env"
        echo "ORG=$ORG" >> ".env"
        echo "IMGNAME=$IMGNAME" >> ".env"
        echo "IMGTAG=$IMGTAG" >> ".env"
        echo "CONTNAME=$CONTNAME" >> ".env"
        echo "NETWORKNAME=$NETWORKNAME" >> ".env"
        docker-compose build --no-cache
        echo "Docker Compose built" >> "ScriptOutput_${currentDate}.txt"
        if $DO_DOCKER_COMPOSE_UP ; then
            docker-compose up -d
            echo "Docker services are up now, checked in" >> "ScriptOutput_${currentDate}.txt"  
        else
            echo "Docker services are down, checked in" >> "ScriptOutput_${currentDate}.txt"
        fi
elif [[ "$updatedDate" -gt "$createdDate" ]]; then 
    echo "Updated is latest"
    start_date=$(date -jf "%Y%m%d%H%M%S" "$updatedDate" "+%s")
    end_date=$(date -jf "%Y%m%d%H%M%S" "$createdDate" "+%s")
    diffMins=$(( ($start_date - $end_date) / (60) ))
    if [[ "$BUILDMINS" -lt "$diffMins" ]]; then
        if [ ! -d "${FILEPATH}" ]; then
            mkdir "${FILEPATH}";
        fi
        cd "${FILEPATH}"
        pwd
        echo "updatedDate---$updatedDate" > "ScriptOutput_${currentDate}.txt"
        echo "createdDate---$createdDate" >> "ScriptOutput_${currentDate}.txt"
        echo "currentDate---$currentDate" >> "ScriptOutput_${currentDate}.txt"
        echo "Found after comparing times -> Docker hub's latest updated image is new; Diff ${diffMins} mins" >> "ScriptOutput_${currentDate}.txt"
        echo "Actual image built time is less i.e. ${diffMins} mins than MAX expexted BUILD TIME i.e. ${BUILDMINS} mins" >> "ScriptOutput_${currentDate}.txt"
        echo "Fetching all new" >> "ScriptOutput_${currentDate}.txt"
        echo "-----------------------------"
        if $IS_CONTAINER_RUNNING ; then
            echo "Container is running"         
        else
            docker-compose down
            echo "Container stopped and removed; Network removed" >> "ScriptOutput_${currentDate}.txt"
        fi
        echo "Image_Created_Date=$currentDate" > ".env"
        echo "ORG=$ORG" >> ".env"
        echo "IMGNAME=$IMGNAME" >> ".env"
        echo "IMGTAG=$IMGTAG" >> ".env"
        echo "CONTNAME=$CONTNAME" >> ".env"
        echo "NETWORKNAME=$NETWORKNAME" >> ".env"
        docker-compose build --no-cache
        echo "Docker Compose built" >> "ScriptOutput_${currentDate}.txt"
        if $DO_DOCKER_COMPOSE_UP ; then
            docker-compose up -d
            echo "Docker services are up now" >> "ScriptOutput_${currentDate}.txt"  
        else
            echo "Docker services are down" >> "ScriptOutput_${currentDate}.txt"
        fi
    elif [[ "$BUILDMINS" -gt "$diffMins" ]]; then
        echo "Docker hub's latest updated image is NOT new; Diff ${diffMins} mins"
        echo "Docker images not fetched"
    else
        echo "Docker hub's latest updated image is NOT new; Diff ${diffMins} mins"
        echo "Docker images not fetched"
    fi
elif [[ "$createdDate" -gt "$updatedDate" ]]; then 
    echo "Created is latest"
    start_date=$(date -jf "%Y%m%d%H%M%S" "$createdDate" "+%s")
    end_date=$(date -jf "%Y%m%d%H%M%S" "$updatedDate" "+%s")
    echo "Docker hub has older docker image than local; Older than $(( ($start_date - $end_date) / (60) ))mins"
fi
echo 
echo "------------end---------------"
rm $PIDFILE

这是我的docker-compose文件

version:  "3.2"
services:
  lamp-alpine:
    build:
      context: .
    container_name: "${CONTNAME}"
    image: "${ORG}/${IMGNAME}:${IMGTAG}"
    ports:
      - "127.0.0.1:80:80"
    networks:
      - private-network 

networks:
  private-network:
    driver: bridge

You can use Watchtower to watch for updates to the image a container is instantiated from and automatically pull the update and restart the container using the updated image. However, that doesn't solve the problem of rebuilding your own custom images when there's a change to the upstream image it's based on. You could view this as a two-part problem: (1) knowing when an upstream image has been updated, and (2) doing the actual image rebuild. (1) can be solved fairly easily, but (2) depends a lot on your local build environment/practices, so it's probably much harder to create a generalized solution for that.

If you're able to use Docker Hub's automated builds, the whole problem can be solved relatively cleanly using the repository links feature, which lets you trigger a rebuild automatically when a linked repository (probably an upstream one) is updated. You can also configure a webhook to notify you when an automated build occurs. If you want an email or SMS notification, you could connect the webhook to IFTTT Maker. I found the IFTTT user interface to be kind of confusing, but you would configure the Docker webhook to post to https://maker.ifttt.com/trigger/`docker_xyz_image_built`/with/key/`your_key`.

如果你需要在本地构建，你至少可以通过在Docker Hub中创建一个连接到你感兴趣的repo的虚拟repo来解决上游映像更新时收到通知的问题。虚拟回购的唯一目的是在重新构建时触发一个webhook(这意味着它的一个链接回购被更新)。如果你能收到这个webhook，你甚至可以用它来触发你这边的重建。

你试过这个吗:https://github.com/v2tec/watchtower。 它是一个简单的工具，运行在docker容器中，监视其他容器，如果它们的基本映像改变了，它将拉出并重新部署。

Docker映像的依赖管理是一个真正的问题。我所在的团队开发了一个名为MicroBadger的工具，通过监视容器图像和检查元数据来帮助解决这个问题。它的功能之一是让你设置一个通知网络钩子，当你感兴趣的图像(例如基本图像)发生变化时，它会被调用。

另一种方法是假设您的基本映像很快就会落后(这很可能发生)，并定期强制应用程序构建另一个映像(例如每周)，如果它发生了更改，则重新部署它。

据我所知，像官方Debian或Java这样的流行基础镜像会更新它们的标记来满足安全修复，所以标记不是不可变的(如果你想要更强的保证，你需要使用参考[image:@digest]，在最新的Docker版本中可用)。因此，如果你要用docker build -pull构建你的映像，那么你的应用程序应该得到你引用的base image标签的最新和最好的。

由于可变标记可能令人困惑，所以最好每次都增加应用程序的版本号，这样至少在您的方面，事情会更清楚。

因此，我不确定在前面的答案之一中建议的脚本是否能完成工作，因为它不重新构建应用程序的映像——它只是更新基本映像标记，然后重新启动容器，但新的容器仍然引用旧的基本映像散列。

我不提倡在容器中运行cron类型的作业(或任何其他进程，除非真的有必要)，因为这违背了每个容器只运行一个进程的原则(关于为什么这样更好有各种各样的争论，所以我不打算在这里讨论)。