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 f

Answer 1

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

Answer 2

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 <container-id>.

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 <container-id>. Then accessed its shell again using nsenter and found that time was now set to Singapore time zone.

docker start <container-id>
docker inspect -f {{.State.Pid}} <container-id>
nsenter -m -u -i -n -p -t <PID> /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.

Answer 3

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 "-static"' -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 ["./main"]

Answer 4

I was facing a time offset of -1hour and 4min

Restarting Docker itself fixed the issue for me.

To set the timezone in general:

1. ssh into your container: docker exec -it my_website_name bash

2. run dpkg-reconfigure tzdata

3. run date

Answer 5

With docker for windows I had to tick

MobyLinuxVM > Settings > Integration Services > Time synchronization 

in Hyper-V manager and it worked

Answer 6

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)"