@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        DockerImage that = (DockerImage) o;
        return registry.equals(that.registry) &&
               repository.equals(that.repository) &&
               tag.equals(that.tag);
    }
Returns a copy of this with registry set to given value
config-provisioning/src/main/java/com/yahoo/config/provision/DockerImage.java