Re: [PATCH] bonding: Prevent deletion of a bond, or the last slave from a bond, with active usage.

Thu, Sep 08, 2016 at 06:32:02PM CEST, jasminder.kaur@hpe.com wrote:

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               The issue of interfaces being arbitrarily changed or deleted is not specific to bonding, and could affect any networking device (physical or virtual).  Thus, if a facility such as this is to be provided, it should be generic, not specific to bonding.

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               Separately, I'm not sure I see the value of such an option.

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Other than administrator error, I'm not sure when bonds (or other

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interfaces) would be randomly deleted.  Are you seeing that happening?

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               Also, this patch does not prevent other errors or malicious change, e.g., "ip link set bondX down" or "ip addr del 1.2.3.4/24" would still cause the service disruption you're trying to avoid.

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               And, lastly, what Jiri said: use netlink for new bonding functionality, not sysfs.

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Re-sending my response as per Jiri's input to avoid top-posting.. Hope this is fine.



Hi Jay,  Hi Jiri,



Thank you for your inputs.



Some of the requests we got for such preventive checks are from Admins working on large scale up systems with multiple NICs, FlexNICs and IP addresses.

§  One use case for these checks is to give an alert, in case of any accidental removals owing to operator errors on large configurations.

§  Another use case is during online maintenance activities such as dynamic patching or a driver load/unload operation.  Admin's would

shut down applications and delete affected interfaces  before unload of a driver. They would prefer to get an alert during delete operation

in case some usages linger around.

If admin is stupid and shoots himself in a foot, it's his problem.
Kernel's work is not to babysit him.

Stop wasting the time.

Such alerts are more useful in Cluster configurations, Network Attached Storage( NAS) configurations, VM configurations with Guests, etc.



So these were mainly the situations that prompted us to add such checks in delete paths.

True these checks are not comprehensive for all use cases, we would like to extend this if it can cover more scenarios.



sysfs based use cases were the ones we noticed for bond/slave configurations. Do you suggest other CLI's such as  “ip link” is more commonly used ?

Possibly if these checks are rearranged a bit in code, multiple such CLI interfaces can be covered ? Please let us know.



Thanks & Regards,

Jasminder