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

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Date:   Fri, 9 Sep 2016 08:38:02 +0200
From:   Jiri Pirko <jiri@...nulli.us>
To:     "Kaur, Jasminder (STSD)" <jasminder.kaur@....com>
Cc:     Jay Vosburgh <jay.vosburgh@...onical.com>,
        "vfalico@...il.com" <vfalico@...il.com>,
        "gospo@...ulusnetworks.com" <gospo@...ulusnetworks.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Gurunath, Vasundhara (STSD)" <vasundhara.gurunath@....com>,
        "Arackal, Paulose Kuriakose (STSD)" 
        <paulose.kuriakose.arackal@....com>
Subject: 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@....com wrote:
>>                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.
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>Hi Jay,  Hi Jiri,
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>Thank you for your inputs.
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>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.
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>§  One use case for these checks is to give an alert, in case of any accidental removals owing to operator errors on large configurations.
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>§  Another use case is during online maintenance activities such as dynamic patching or a driver load/unload operation.  Admin's would
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>shut down applications and delete affected interfaces  before unload of a driver. They would prefer to get an alert during delete operation
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>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.


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>Such alerts are more useful in Cluster configurations, Network Attached Storage( NAS) configurations, VM configurations with Guests, etc.
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>So these were mainly the situations that prompted us to add such checks in delete paths.
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>True these checks are not comprehensive for all use cases, we would like to extend this if it can cover more scenarios.
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>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 ?
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>Possibly if these checks are rearranged a bit in code, multiple such CLI interfaces can be covered ? Please let us know.
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>Thanks & Regards,
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>Jasminder
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