Forum Discussion
AltocumulusHow to add a timestamp on iRule
Nacreous
Patrik_Jonsson wrote:
Using MD5 is another method but without something in the iRule content to make it unique you won't be able to detect propagation if the iRule is redeployed unmodified. When the aim is propagation verification regardless of content each item has to be unique.
Either I don't understand you, or you don't understand me. Irules consists of characters, if even one character changes the whole MD5 sum changes. 🙂
As to your first question... its one or the other 🙂 You illustrated my point exactly... if you read my post carefully I said unmodified. This means no character has changed therefore the md5 will not change. Now what happens if they re-deployed the same iRule? You will not be able to tell if it has been propagated as the md5 value never changed.
They have a pipeline which updates iRules so he'd know if the iRule was successfully updated or not on the device which syncs data to the other devices.
He want's to make sure that the same iRule is deployed on all devices. If the md5 is the same, the iRules are the same. I'd say that's a pretty good way to know if the iRules matches across devices or not.
- Kevin_Davies
Yes but it does not solve one of the stated goals of the original question - "validate sync between many nodes of the same cluster". What you propose validates they rules are the same but not the sync process is actually working. Why is this not the same thing?
I push A to a device and I want to make sure all of my cluster ends up with A.
Your solution works fine. There is clearly evidence sync is working.
Now it I push B and I want to make sure all of my cluster ends up with B.
Again works fine. There is clearly evidence sync is working as B is different from A.
Now I push B again and I want to make sure all my cluster ends up with B.
This is where it falls down. Even if the cluster has B already there is no evidence that sync is working because you do not provide a unique discriminator between what your pushing and what is already deployed. So you're saying that if you push the exact same iRule again there is no way of knowing if the iRule that already is running on all devices is synced again?
- Kevin_Davies
Patrik_Jonsson wrote:
So you're saying that if you push the exact same iRule again there is no way of knowing if the iRule that already is running on all devices is synced again?
Bingo. Hence something unique needs to be added, even if you want to use MD5.
No bingo for me. Why would you want to validate that something is synced that is already synced?
- Kevin_Davies
Patrik_Jonsson wrote:
No bingo for me. Why would you want to validate that something is synced that is already synced?
See original question - "validate sync between many nodes of the same cluster" If I agree to your interpretation I do not see how your suggestion solves the issue either. 🙂
