How can I reset system time to network time from the command line?

Question

I'm having trouble defining object-level permissions for foreign-key relationships in my ModelViewSet. I'm not sure if it's entirely possible what I'm trying to do or if there's a better solution, but any hint in the right direction would be much appreciated. I've shortened the models and serializers for the sake of brevity.

I have the following models:

class Team(models.Model):
    name = models.CharField(max_length=50)

class CustomUser(AbstractUser):
    teams = models.ManyToManyField(Team)

class Client(models.Model):
    name = models.CharField(max_length=50)
    owner = models.ForeignKey(Team, on_delete=models.CASCADE)

class FinancialAccount(models.Model):
    account_name = models.CharField(max_length=50)
    client = models.ForeignKey(Client, on_delete=models.CASCADE)

Then I have the following serializers:

class ClientSerializer(serializers.ModelSerializer):
    class Meta:
        model = Client
        fields = ('name', 'owner')

class FinancialAccountSerializer(serializers.ModelSerializer):
    owner = serializers.SerializerMethodField()

    class Meta:
        model = FinancialAccount
        fields = ('name', 'client', 'owner')

    def get_owner(self, obj):
        return client.owner.name

Then I'm trying to define a permission that I can use in all of my ModelViewSets. I'd like it to be somewhat dynamic as I have many more models than the ones above that are related to Client or even below FinancialAccount. The permission and viewset are as follows:

class IsOwnerTeam(permissions.BasePermission):
    def has_object_permission(self, request, view, obj):
        teams = request.user.teams.values_list('name', flat=True)
        return obj.owner in teams

class FinancialAccountViewSet(viewsets.ModelViewSet):
    serializer_class = FinancialAccountSerializer
    permission_classes = (IsOwnerTeam, )

    def get_queryset(self):
        teams = self.request.user.teams.all()
        clients = Client.objects.filter(owner__in=teams)
        return FinancialAccount.objects.filter(account__in=accounts)

So, right now I'm receiving this error: 'FinancialAccount' object has no attribute 'owner', which makes sense because I don't have an owner field on the FinancialAccount object. But, I thought if I had an owner field in the serializer (and put an owner field in each of the serializers) I could retrieve it that way. Any help would be appreciated!

Solution 1

ntpdate deprecated

ntpdate is deprecated, read more here: http://support.ntp.org/bin/view/Dev/DeprecatingNtpdate

For a one-shot approach

• install the ntp package with sudo apt-get install ntp
• set a server in your /etc/ntp.conf
• and use sudo ntpd -q -g -x -n for a one-time sync.

This also works for deviations up to 68 years.

Alternatively, go to "System Settings" → "Time and Date" (I'm not sure its the correct translation) to enable Network time. Note that you can't specify a server there.

Solution 2

EDIT ntpdate is now deprecated, see @Jan answer for a more secure solution.

Firt of all, you have to install the NTP server (if you don't have it yet) so

sudo apt-get install ntp

Then, check if ntp is running with

sudo service ntp status

If it's not running, you can simply type

sudo service ntp start

Then to update the time

sudo ntpdate -u time.nist.gov

time.nist.gov is not the only one of course. Here there is a list of timeserver you can alternatively use. source here

Comments

[Jetson Earth]

Using ntpdate when there's a ntp server running is discouraged and ntpdate is deprecated.

[tigerjack]

@Jan I didn't know that, I always used this command. Why it is deprecated? Could you provide a link?

[Jetson Earth]

support.ntp.org/bin/view/Dev/DeprecatingNtpdate

[tigerjack]

@Jan thanks for the info, I've updated my answer

[Fabby]

support.ntp.org/bin/view/Dev/DeprecatingNtpdate

[Melebius]

What is the purpose of echo in your script?

[Ryan Dines]

with the backtick it just indicates a line of code as opposed to quotes, which just writes to standard out, then you suppress the output by redirecting it to /dev/null, idk, i think maybe you can leave them out on ubuntu? I know for Centos/RHEL I needed them