Need to tell eureka client running in Docker to use host's IP

[cer]

I am running a Spring Cloud application inside a Docker container.
While I can tell Eureka to use the exposed port (e.g. EUREKA_INSTANCE_NON_SECURE_PORT: 8081) , it doesn't seem to let you tell it to register using the host's ip address.
Instead, eureka registers the instance using the container's ip address.
That fine unless I want to access the container from another host.
What would be great is the ability to set an environment variable such as EUREKA_INSTANCE_NON_SECURE_HOST: docker_host_ip_address

[spencergibb]

I wonder if eureka.instance.hostname will work. If not, then we'll have to do something to fix it.

[brenuart]

And what about:

• eureka.instance.prefer-ip-address=true
• eureka.instance.ip-address=

[cer]

Difficult to tell from looking at the class in isolation. Depends on
whether getHostName(refresh) is called with refresh=true or false.

[spencergibb]

@cer maybe an option to disable the refresh

[cer]

I haven't looked at Spring Cloud enough to know precise what refresh is
intended to do.
However, I think that a user specified host name/ip address should always
take precedence.

[brenuart]

Maybe I don't get it, but setting eureka.instance.hostname to the desired value should work (at least it does on our side).
If you set eureka.instance.prefer-ip-address=true, then the registration with Eureka will instead use the IP address specified by eureka.instance.ip-address (which defaults to host's IP after resolving).

@cer: the user specified value takes precedence over the default values. Do you see a different behaviour?

[spencergibb]

@brenuart we used to ignore the refresh, but then I did 9149319 which will refresh at somepoint in netflix code. @cer, I agree, we just have trouble knowing when the value was user specified or not, so either another user specified hostname field or the flag to not refresh.

[brenuart]

@spencergibb Ok - I see. Sorry, I wasn't aware of that change.
To be honest, we used to override part of the EurekaInstanceConfigBean to add some validation and other useful default values/behaviour. To make it short, we moved the initialisation of default values out of the config bean to the method that creates it. The config bean is now a simple POJO and we are not "hit" by your latest change...
I should definitely create a PR with those changes for you to see and pickup what you believe is interesting.

[ccit-spence]

@cer @spencergibb Having a slightly more complicated version of the same problem. I am experiencing the same issue for the host. On top of that the container is launched with -P meaning a random host port is assigned. With the current setup there is no way to get that random port assignment. The port is being pulled from server.port.

Another note, about assigning something within eureka.instance.hostname or eureka.instance.ip-address is that if this is a docker cluster in our case AWS ECS. The host and IP can't be statically configured within properties.

[ccit-spence]

Something that can be done from docker is just using the docker run -h hostname or ip Eureka will pick up the host name since it it written to the etc/hosts file

Not sure yet how to handle this for a cluster.

[ccit-spence]

Update: Further testing with AWS ECS even with adding the hostname to the properties it does not work. Unless all instances are docker containers i.e. Eureka, Zuul and UI and API services on the same host. Not sure If I am missing something. It seems that Ribbon is looking for something different than what Eureka is showing via the UI. Even if I could get it to work. As soon as the docker container switched to a different EC2 container the old hostname would be invalid.

[cer]

What do you mean by "docker container switched to a different EC2 container" exactly?

[ccit-spence]

@cer In ECS you have a cluster of EC2 instances. Due to the nature of EC2 unless you specify a Service to run on only one EC2 instance it can appear anywhere within the cluster.

That being said I now have ECS working for Spring Cloud. The solution is to curl the hostname of the host from within the Docker container during its boot process and assign the hostname to an environment variable. Then add the discovered hostname to the Eureka instance metadata.

[rozhok]

@cer look at this - #30
I've got same problem - AWS, Docker and I've resolved it using proposed custom configurations.

[ccit-spence]

@rozhok Are you doing something like the below? This is how I managed to get ECS to work.

entrypoint.sh

#!/bin/sh
export HOST=$(curl --retry 5 --connect-timeout 3 -s 169.254.169.254/latest/meta-data/local-hostname)
export LOCAL_IP=$(curl --retry 5 --connect-timeout 3 -s 169.254.169.254/latest/meta-data/local-ipv4)
exec "$@"

Dockerfile

FROM privaterepo/oracle-java8

RUN bash -c 'apt-get -qq update'
RUN bash -c 'DEBIAN_FRONTEND=noninteractive apt-get install -y curl'

EXPOSE 8080

COPY *.jar target/app.jar

COPY entrypoint.sh /usr/local/bin/entrypoint.sh

RUN touch target/app.jar

RUN chmod +x /usr/local/bin/entrypoint.sh

ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]

CMD java -jar target/app.jar

[rozhok]

No, I've created custom Eureka Config so I don't need to setup additional scripts in Dockerfile. All stuff are described in #30 .

[rozhok]

Another one approach described in Spring Cloud Netflix docs:

@Bean
@Profile("docker")
public EurekaInstanceConfigBean eurekaInstanceConfig() {
    EurekaInstanceConfigBean config = new EurekaInstanceConfigBean();
    AmazonInfo info = AmazonInfo.Builder.newBuilder().autoBuild("eureka");
    config.setDataCenterInfo(info);
    info.getMetadata().put(AmazonInfo.MetaDataKey.publicHostname.getName(), info.get(AmazonInfo.MetaDataKey.publicIpv4));
    config.setHostname(info.get(AmazonInfo.MetaDataKey.publicHostname));
    config.setIpAddress(info.get(AmazonInfo.MetaDataKey.publicIpv4));
    config.setNonSecurePort(port);
    return config;
}

This will put proper IP (public in my case, but you may change it to local) and port into Eureka registry.
Don't forget to add proper spring profile into Java env props, like this:

FROM java:8
EXPOSE 14862
ENV JAVA_OPTS -Dspring.profiles.active=docker
ADD build/distributions/portal.tar /
ENTRYPOINT ["/portal/bin/portal"]

[spencergibb]

@cer @rozhok @brenuart @ccit-spence anyone still having issues that we need to address?

[ccit-spence]

My solution works fine for me.

[rozhok]

@spencergibb I'm using solution described above. A little bit hackish but fine at the moment.

[brenuart]

I'm fine with this.

[Dreampie]

It can be used to do my own server not AWS？

@Bean
@Profile("docker")
public EurekaInstanceConfigBean eurekaInstanceConfig() {
    EurekaInstanceConfigBean config = new EurekaInstanceConfigBean();
    AmazonInfo info = AmazonInfo.Builder.newBuilder().autoBuild("eureka");
    config.setDataCenterInfo(info);
    info.getMetadata().put(AmazonInfo.MetaDataKey.publicHostname.getName(), info.get(AmazonInfo.MetaDataKey.publicIpv4));
    config.setHostname(info.get(AmazonInfo.MetaDataKey.publicHostname));
    config.setIpAddress(info.get(AmazonInfo.MetaDataKey.publicIpv4));
    config.setNonSecurePort(port);
    return config;
}

[rozhok]

@Dreampie not, it won't be used on your own infrastructure since it using AWS-specific SDK.

[Dreampie]

@rozhok thank you. and how can eureka client registered with host ip，not docker container ip？if use --net=host always return 127.0.0.1

[rozhok]

Use some env variables passed into docker on startup time.

[Dreampie]

@rozhok but if this machine's ip changed, must recreate container?

[rozhok]

Sure.

[rozhok]

Or trigg some API insinde container to reload eureka configuration. Something like /api/eureka/changeIp etc. There is a lot of ways to solve this task but non of them are obvious or elegant. Sad.

[Dreampie]

💦thanks

[asarkar]

@Dreampie Using the custom Eureka config as in your post, what do the application.yml and bootstrap.yml look like?

[cswanghan]

is there any update about this issue?

[spencergibb]

@cswanghan no, it was closed in 2015

[momentum123]

@spencergibb im still facing the issue

[wenfei3]

@momentum123
me too

[niall-morgan]

It can be used to do my own server not AWS？

@Bean
@Profile("docker")
public EurekaInstanceConfigBean eurekaInstanceConfig() {
    EurekaInstanceConfigBean config = new EurekaInstanceConfigBean();
    AmazonInfo info = AmazonInfo.Builder.newBuilder().autoBuild("eureka");
    config.setDataCenterInfo(info);
    info.getMetadata().put(AmazonInfo.MetaDataKey.publicHostname.getName(), info.get(AmazonInfo.MetaDataKey.publicIpv4));
    config.setHostname(info.get(AmazonInfo.MetaDataKey.publicHostname));
    config.setIpAddress(info.get(AmazonInfo.MetaDataKey.publicIpv4));
    config.setNonSecurePort(port);
    return config;
}

EurekaInstanceConfigBean is private in that package .. not sure how this would be implemented.

[spencergibb]

EurekaInstanceConfigBean is public

spring-cloud-netflix/spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/EurekaInstanceConfigBean.java

Line 42 in c60b6db

public class EurekaInstanceConfigBean

[secesor]

EurekaInstanceConfigBean is public

spring-cloud-netflix/spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/EurekaInstanceConfigBean.java

Line 42 in c60b6db

public class EurekaInstanceConfigBean

It's the class that is public but the constructor is private.
See

spring-cloud-netflix/spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/EurekaInstanceConfigBean.java

Line 287 in c60b6db

private EurekaInstanceConfigBean() {

I have the same issue running my app inside DevContainer (docker behind the scenes).
How can I then create an instance of EurekaInstanceConfigBean?

[spencergibb]

Use the public constructor. InetUtils is also a bean.

public EurekaInstanceConfigBean(InetUtils inetUtils) {
    this.inetUtils = inetUtils;
    this.hostInfo = this.inetUtils.findFirstNonLoopbackHostInfo();
    this.ipAddress = this.hostInfo.getIpAddress();
    this.hostname = this.hostInfo.getHostname();
}