How to make sure docker s time syncs with that of the host

Question

I have dockers running on Linode servers  At times  I see that the time is not right on the dockers  Currently I have changed the run script in every docker to include the following lines of code   yum install -y ntp service ntpd stop ntpdate pool ntp org   What I would ideally like to do however is that the docker should sync time with the host  Is there a way to do this

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If you are using boot2docker and ntp doesn t work inside the docker VM  you are behind a proxy which does not forward ntp packets  but your host is time-synced  you can run the following from your host   docker-machine ssh default  sudo date -u   date -u   m d H M Y     This way you are sending your machine s current time  in UTC timezone  as a string to set the docker VM time using date  again in UTC timezone    NOTE  in Windows  inside a bash shell  from the msys git   use   docker-machine exe ssh default  sudo date -u   date -u   m d H M Y

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If you re using docker-machine  the virtual machines can drift  To update the clock on the virtual machine without restarting run   docker-machine ssh  lt machine-name default gt  sudo ntpclient -s -h pool ntp org   This will update the clock on the virtual machine using NTP and then all the containers launched will have the correct date

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With docker for windows I had to tick   MobyLinuxVM  gt  Settings  gt  Integration Services  gt  Time synchronization    in Hyper-V manager and it worked

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The source for this answer is the comment to the answer at  Will docker container auto sync time with the host machine   After looking at the answer  I realized that there is no way a clock drift will occur on the docker container  Docker uses the same clock as the host and the docker cannot change it  It means that doing an ntpdate inside the docker does not work   The correct thing to do is to update the host time using ntpdate  As far as syncing timezones is concerned  -v  etc localtime  etc localtime ro works

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Windows users  The solution is very simple  Simply open a powershell prompt and enter  docker run --privileged --rm alpine date -s  quot   Get-Date   datetime   UtcNow  -UFormat  quot   Y- m- d  H  M  S quot   quot  To check that it works  run the command  docker run --rm -it alpine date  My solution is inspired by something I found in docker forum thread  Anyways  it was the only solution that worked for me on docker desktop  except for restarting my machine  which also works   Here s a link to the original thread  https   forums docker com t syncing-clock-with-host 10432 23 The difference between the thread answer and mine is that mine converts the time to UTC time  which is necessary for e g  AWS  Otherwise  the original answer from the forum looks like this  docker run --privileged --rm alpine date -s  quot   date -u  quot   Y- m- d  H  M  S quot   quot

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Although this is not a general solution for every host  someone may find it useful  If you know where you are based  UK for me  then look at tianon s answer here   FROM alpine 3 6 RUN apk add --no-cache tzdata ENV TZ Europe London   This is what I added to my Dockerfile   and the timezone problem was fixed

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This is what worked for me with a Fedora 20 host  I ran a container using   docker run -v  etc localtime  etc localtime ro -i -t mattdm fedora  bin bash   Initially  etc localtime was a soft link to  usr share zoneinfo Asia Kolkata which Indian Standard Time  Executing date inside the container showed me same time as that on the host  I exited from the shell and stopped the container using docker stop  lt container-id gt    Next  I removed this file and made it link to  usr share zoneinfo Singapore for testing purpose  Host time was set to Singapore time zone  And then did docker start  lt container-id gt   Then accessed its shell again using nsenter and found that time was now set to Singapore time zone   docker start  lt container-id gt  docker inspect -f    State Pid    lt container-id gt  nsenter -m -u -i -n -p -t  lt PID gt   bin bash   So the key here is to use -v  etc localtime  etc localtime ro when you run the container first time  I found it on this link   Hope it helps

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I was facing a time offset of -1hour and 4min  Restarting Docker itself fixed the issue for me   To set the timezone in general    ssh into your container  docker exec -it my website name bash run dpkg-reconfigure tzdata run date

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I have the following in the compose file volumes    -  quot  etc timezone  etc timezone ro quot    -  quot  etc localtime  etc localtime ro quot   Then all good in Gerrit docker with its replication log set with correct timestamp

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You can add your local files   etc timezone and  etc localtime  as volume in your Docker container  Update your docker-compose yml with the following lines  volumes      -  quot  etc timezone  etc timezone ro quot      -  quot  etc localtime  etc localtime ro quot   Now the container time is the same as on your host

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docker-compose usage  Add  etc localtime  etc localtime ro to the volumes attribute  version   3   services    a-service        image  service-name       container name  container-name       volumes          -  etc localtime  etc localtime ro

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Docker Usage Here s a complete example which builds a docker image for a go app in a multistage build  It shows how to include the timezone in your image  FROM golang latest as builder  WORKDIR  app  ENV GO111MODULE on       CGO ENABLED 0       GOOS linux       GOARCH amd64  COPY go mod   COPY go sum    RUN go mod download  COPY      RUN go build -a -installsuffix cgo -ldflags  -extldflags  quot -static quot   -o main      Certs FROM alpine latest as locals  RUN apk --update --no-cache add ca-certificates  RUN apk add --no-cache tzdata      App FROM scratch   WORKDIR  root   COPY --from locals  etc ssl certs ca-certificates crt  etc ssl certs ca-certificates crt  COPY --from builder app main    COPY --from builder app templates   templates  COPY --from locals  usr share zoneinfo  usr share zoneinfo  ENV TZ Asia Singapore  EXPOSE 8000  CMD   quot   main quot

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Enabling Hyper-V in Windows Features solved the problem  Windows Features

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I ve discovered that if your computer goes to sleep then the docker container goes out of sync   https   forums docker com t time-in-container-is-out-of-sync 16566  I have made a post about it here  Certificate always expires 5 days ago in Docker

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For docker on macOS  you can use docker-time-sync-agent  It works for me

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For me  restarting Docker Desktop did not help  Shutting down Win10 and start it again  it did help

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It appears there can by time drift if you re using Docker Machine  as this response suggests  https   stackoverflow com a 26454059 105562   due to VirtualBox    Quick and easy fix is to just restart your VM   docker-machine restart default

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This will reset the time in the docker server   docker run --rm --privileged alpine hwclock -s   Next time you create a container the clock should be correct   Source  https   github com docker for-mac issues 2076 issuecomment-353749995

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For whatever reason none of these answers solved my problem  It had nothing to do with the docker date time for the images I was creating   It had to do with my local WSL date time  Once I ran sudo ntpdate-debian everything worked  If you don t have ntp just install it and run the command   If you aren t using debian then you probably won t have the shell script ntpdate-debian  but you can use ntpd -gq as well   Basically just update the date for your main WSL distro

[docker] How to make sure docker's time syncs with that of the host?

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