[Evergreen-general] Question about search engine bots & DB CPU spikes
JonGeorg SageLibrary
jongeorg.sagelibrary at gmail.com
Fri Dec 3 13:37:42 EST 2021
Thank you!
-Jon
On Fri, Dec 3, 2021 at 8:10 AM Blake Henderson via Evergreen-general <
evergreen-general at list.evergreen-ils.org> wrote:
> JonGeorg,
>
> This reminds me of a similar issues that we had. We resolved it with this
> change to NGINX. Here's the link:
>
>
> https://git.evergreen-ils.org/?p=working/OpenSRF.git;a=shortlog;h=refs/heads/user/blake/LP1913610_nginx_request_limits
>
> and the bug:
> https://bugs.launchpad.net/evergreen/+bug/1913610
>
> I'm not sure that it's the same issue though, as you've shared a search
> SQL query and this solution addresses external requests to
> "/opac/extras/unapi"
> But you might be able to apply the same nginx rate limiting technique here
> if you can detect the URL they are using.
>
> There is a tool called "apachetop" which I used in order to see the URL's
> that were being used.
>
> apt-get -y install apachetop && apachetop -f
> /var/log/apache2/other_vhosts_access.log
>
> and another useful command:
>
> cat /var/log/apache2/other_vhosts_access.log | awk '{print $2}' | sort |
> uniq -c | sort -rn
>
> You have to ignore (not limit) all the requests to the Evergreen gateway
> as most of that traffic is the staff client and should (probably) not be
> limited.
>
> I'm just throwing some ideas out there for you. Good luck!
>
> -Blake-
> Conducting Magic
> Can consume data in any format
> MOBIUS
>
> On 12/2/2021 9:07 PM, JonGeorg SageLibrary via Evergreen-general wrote:
>
> I tried that and still got the loopback address, after restarting
> services. Any other ideas? And the robots.txt file seems to be doing
> nothing, which is not much of a surprise. I've reached out to the people
> who host our network and have control of everything on the other side of
> the firewall.
> -Jon
>
>
> On Wed, Dec 1, 2021 at 3:57 AM Jason Stephenson <jason at sigio.com> wrote:
>
>> JonGeorg,
>>
>> If you're using nginx as a proxy, that may be the configuration of
>> Apache and nginx.
>>
>> First, make sure that mod_remote_ip is installed and enabled for Apache 2.
>>
>> Then, in eg_vhost.conf, find the 3 lines the begin with
>> "RemoteIPInternalProxy 127.0.0.1/24" and uncomment them.
>>
>> Next, see what header Apache checks for the remote IP address. In my
>> example it is "RemoteIPHeader X-Forwarded-For"
>>
>> Next, make sure that the following two lines appear in BOTH "location /"
>> blocks in the ngins configuration:
>>
>> proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
>> proxy_set_header X-Forwarded-Proto $scheme;
>>
>> After reloading/restarting nginx and Apache, you should start seeing
>> remote IP addresses in the Apache logs.
>>
>> Hope that helps!
>> Jason
>>
>>
>> On 12/1/21 12:53 AM, JonGeorg SageLibrary wrote:
>> > Because we're behind a firewall, all the addresses display as
>> 127.0.0.1.
>> > I can talk to the people who administer the firewall though about
>> > blocking IP's. Thanks
>> > -Jon
>> >
>> > On Tue, Nov 30, 2021 at 8:20 PM Jason Stephenson via Evergreen-general
>> > <evergreen-general at list.evergreen-ils.org
>> > <mailto:evergreen-general at list.evergreen-ils.org>> wrote:
>> >
>> > JonGeorg,
>> >
>> > Check your Apache logs for the source IP addresses. If you can't
>> find
>> > them, I can share the correct configuration for Apache with Nginx so
>> > that you will get the addresses logged.
>> >
>> > Once you know the IP address ranges, block them. If you have a
>> > firewall,
>> > I suggest you block them there. If not, you can block them in Nginx
>> or
>> > in your load balancer configuration if you have one and it allows
>> that.
>> >
>> > You may think you want your catalog to show up in search engines,
>> but
>> > bad bots will lie about who they are. All you can do with
>> misbehaving
>> > bots is to block them.
>> >
>> > HtH,
>> > Jason
>> >
>> > On 11/30/21 9:34 PM, JonGeorg SageLibrary via Evergreen-general
>> wrote:
>> > > Question. We've been getting hammered by search engine bots [?],
>> but
>> > > they seem to all query our system at the same time. Enough that
>> it's
>> > > crashing the app servers. We have a robots.txt file in place.
>> I've
>> > > increased the crawling delay speed from 3 to 10 seconds, and have
>> > > explicitly disallowed the specific bots, but I've seen no change
>> > from
>> > > the worst offenders - Bingbot and UT-Dorkbot. We had over 4k hits
>> > from
>> > > Dorkbot alone from 2pm-5pm today, and over 5k from Bingbot in the
>> > same
>> > > timeframe. All a couple hours after I made the changes to the
>> robots
>> > > file and restarted apache services. Which out of 100k entries in
>> the
>> > > vhosts files in that time frame doesn't sound like a lot, but the
>> > rest
>> > > of the traffic looks normal. This issue has been happening
>> > > intermittently [last 3 are 11/30, 11/3, 7/20] for a while, and
>> > the only
>> > > thing that seems to work is to manually kill the services on the
>> DB
>> > > servers and restart services on the application servers.
>> > >
>> > > The symptom is an immediate spike in the Database CPU load. I
>> start
>> > > killing all queries older than 2 minutes, but it still usually
>> > > overwhelms the system causing the app servers to stop serving
>> > requests.
>> > > The stuck queries are almost always ones along the lines of:
>> > >
>> > > -- bib search: #CD_documentLength #CD_meanHarmonic
>> #CD_uniqueWords
>> > > from_metarecord(*/BIB_RECORD#/*) core_limit(100000)
>> > > badge_orgs(1,138,151) estimation_strategy(inclusion)
>> skip_check(0)
>> > > check_limit(1000) sort(1) filter_group_entry(1) 1
>> > > site(*/LIBRARY_BRANCH/*) depth(2)
>> > > +
>> > > | | WITH w AS (
>> > > | | WITH */STRING/*_keyword_xq AS (SELECT
>> > > +
>> > > | | (to_tsquery('english_nostop',
>> > > COALESCE(NULLIF( '(' ||
>> > >
>> >
>> btrim(regexp_replace(split_date_range(search_normalize(replace(replace(uppercase(translate_isbn1013(E'1')),
>> >
>> > > */LONG_STRING/*))),E'(?:\\s+|:)','&','g'),'&|') || ')', '()'),
>> > '')) ||
>> > > to_tsquery('simple', COALESCE(NULLIF( '(' ||
>> > >
>> >
>> btrim(regexp_replace(split_date_range(search_normalize(replace(replace(uppercase(translate_isbn1013(E'1')),
>> >
>> > > */LONG_STRING/*))),E'(?:\\s+|:)','&','g'),'&|') || ')', '()'),
>> > ''))) AS
>> > > tsq,+
>> > > | | (to_tsquery('english_nostop',
>> > > COALESCE(NULLIF( '(' ||
>> > > btrim(regexp_replace(split_date_range(search_normalize
>> > > 00:02:17.319491 | */STRING/* |
>> > >
>> > > And the queries by DorkBot look like they could be starting the
>> > query
>> > > since it's using the basket function in the OPAC.
>> > >
>> > > "GET
>> > >
>> >
>> /eg/opac/results?do_basket_action=Go&query=1&detail_record_view=*/LONG_STRING/*&search-submit-go=Search&no_highlight=1&modifier=metabib&select_basket_action=1&qtype=keyword&fg%3Amat_format=1&locg=112&sort=1
>> >
>> > > HTTP/1.0" 500 16796 "-" "UT-Dorkbot/1.0"
>> > >
>> > > I've anonymized the output just to be cautious. Reports are run
>> > off the
>> > > backup database server, so it cannot be an auto generated
>> > report, and it
>> > > doesn't happen often enough for that either. At this point I'm
>> > tempted
>> > > to block the IP addresses. What strategies are you all using
>> to deal
>> > > with crawlers, and does anyone have an idea what is causing this?
>> > > -Jon
>> > >
>> > > _______________________________________________
>> > > Evergreen-general mailing list
>> > > Evergreen-general at list.evergreen-ils.org
>> > <mailto:Evergreen-general at list.evergreen-ils.org>
>> > >
>> >
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>> > <
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>> > >
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