Archive for the ‘Uncategorized’ Category

Learning from Operational mistakes

February 2nd, 2019 No comments

In the world of Ops, it’s always good to learn from mistakes. It’s not good enough that we solved a problem (*fix*), but we must also do a post-mortem to understand what went wrong (*root cause*), what can we do to prevent it in the future (*long term solution*).

I am of the opinion that long term solutions are preferred to short term fixes (hacks!). But long term solutions are not easy, they almost always require understanding the root cause, and that is not always obvious.

After any incidents, crisis, problems, whatever you want to call it, make sure you have a *blame-free* post-mortem. This is very important. We are not looking to blame anyone, we should be focusing on the root cause and how can it be prevented from happening again. Going into a post-mortem with the right mind-set also help make the process go much smoother. You will get better cooperation from involved parties. It’s a team effort, to improve everyone’s job.

The process should be something like this.

  • Assign an owner of the post-mortem process. Usually the lead engineer involved in the incident. That person is empowered to call for help from anyone needed.
  • Assign a specific time-frame for when the post-mortem must conclude by. You do not want to let it drag on. Let’s get it done and move on. Recommend no more than two weeks from date of incident.
  • Communicated what is expected of the post-mortem output.
    • When — Timeline of incidents
    • What — specific details of alerts, failures, etc.
    • Communications during the incidents — within team, with other teams, internal and external (customers, press).
    • Root Cause Analysis
    • Prevention
      • Training – better training
      • Monitoring – better monitoring (add monitor, alerts)
      • Failure detection – missed failures
      • SPOF – Single Point of Failure. Add redundancies. Re-architecture.
      • etc.

It’s good if we can learn from past mistakes. It is even better if we can learn from others’ mistakes!

Here is the start of a list of Operational mistakes published on the web. I will be adding more as I find them. Feel free to submit any that I missed. Thanks!



Very nice post from David Henke:

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USB Ethernet Adapters for TiVo

March 27th, 2018 No comments

USB Ethernet Adapters for TiVo


Here is a collected list of USB adapters I got from http://www.tivoco

I bought a cheap one (Farallon USB1.1 to ethernet) for $13 from Computer
Geek, and it worked great. Just plug-n-play 🙂

09/11/2005Got word from Antonio Carlos that a Linksys USB200M
works great.

06/17/2004 I’ve received feedback from Rob Clark
that a D-Link DSB-H3ETX (USB to enet adapter) also work.
He bought his locally for $15 and the link he sent is

Basically any USB-enet adapters that uses the Pegasus chipset should
work with Tivo as Linux has driver support for that chip.

3Com USB Ethernet 3C460B

USB 10/100 Fast Ethernet
USB HPNA/Ethernet

Accton USB 10/100 Ethernet Adapter
SpeedStream USB 10/100 Ethernet

ADMtek ADM8511 Pegasus II USB Ethernet
ADMtek AN986 Pegasus USB Ethernet (eval. board)

Allied Telesyn Int. AT-USB100

Belkin F5D5050 USB Ethernet

Billionton USB-100
Billionton USBE-100
Billionton USBEL-100
Billionton USBLP-100

iPAQ Networking 10/100 USB

Corega FEter USB-TX

D-Link DSB-650
D-Link DSB-650TX
D-Link DSB-650TX(PNA)

Elsa Micolink USB2Ethernet

Hawking UF100 10/100 Ethernet


Kingston KNU101TX Ethernet


Linksys USB100TX
Linksys USB10TX
Linksys USB Ethernet Adapter
Linksys USB USB10TX
Linksys USB100M
Linksys USB200M


SpeedStream USB 10/100 Ethernet

smartNIC 2 PnP Adapter

SMC 202 USB Ethernet

SOHOware NUB100 Ethernet

Tin “Tin Man” Le /
[email protected]

Tin’s Home…

Last Updated: $Date: 2003/08/19 04:32:49 $

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LinkedIn Celebrate 500M members April, 2017

April 28th, 2017 No comments

LinkedIn 500M members celabratory picture.

Big celebration for LinkedIn as the company hits 500M + members.

This picture was at LinkedIn HQ in Sunnyvale.  I am the guy in the middle of that red circle.

The picture was taken by a mavic pro drone, flying above the building.  The drone belongs to one of my colleague.



Kibana 4 with tribe node MasterNotDiscoveredException

December 19th, 2015 No comments

I use tribe nodes quite a lot at $work. It’s how we federate disparate ELK clusters and able to search across them. There are many reasons to have distinct ELK clusters in each data center and/or region.

Some of these are:

1. Elasticsearch does not work well when there is network latencies, which is guaranteed when your nodes are located geographically distant places. You could spend a lot of money to get fast network connection, or you can just have only local clusters. (Me? I pick saving money and avoiding head aches :-)).

2. It can get insanely expensive to create an ES cluster that span data centers/regions. The network bandwidth requirement, the data charges, the care and feeding of such a latency sensitive cluster…. OMG!

3. I don’t really think a 3rd reason is needed.

Although tribe nodes are great for federating ES clusters, there are some quirks in setting them up and caring for them (not as bad as ES clusters that span datacenter though).

One big gotcha for many people who are setting up tribe nodes for the first time is that tribe node can not create index. Tribe can only update, modify an existing index. What this mean is that if you point Kibana at a tribe node, you must first make sure you Kibana index is already created in one of the downstream ES cluster. Otherwise, you will have to create it yourself.

Otherwise, the first time you create an index pattern and tried to save it, you will get an error similar to the subject of this post.


The error message is wrong and misleading. It has nothing to do with Master node. It has everything to do with tribe node not able to create (PUT) a Kibana index.

Personally, I prefer to make the Kibana index that I use with tribe to have its own unique name. So I run a dedicated Kibana instance pointing to the dedicated tribe (client) node.

Here are the steps I do to get a tribe node and its associated Kibana ready for use.

1. Configure the tribe node to know all the ES clusters I want to federate data from.

tribe.elasticsearch.yml: toplevel_tribe ${HOSTNAME}
node.master: false false
  DC1-appservice: logging-DC1
     network.publish_host: ${HOSTNAME}
  DC2-appservice: logging-DC2
     network.publish_host: ${HOSTNAME}
   DC3.....etc to DCNN

  my-es-dedicated-config-cluster: es-config-CORP
     network.publish_host: ${HOSTNAME}

 on_conflict: prefer_my-es-dedicated-config-cluster

2. Now pre-create the Kibana index in my-ES-dedicated-config-cluster. This is a small cluster in my admin/corp data center that is only for housing configurations, Kibana dashboards, etc.

3. A simpler and more correct way is to temporary point Kibana to the dedicated ES cluster (instead of the tribe).

Do this via this setting in your kibana.yml file:

# The Elasticsearch instance to use for all your queries.
elasticsearch.url: “http://ES-node:9200”

Start Kibana, let it create the index.  Then stop it, change the setting back to point to your tribe node.

Doing it this way ensure that your kibana is correct.

curl command for pre-creating kibana (3 and 4) index:

curl -s -XPUT "http://localhost:9200/kibana3-int/" -d '{ "settings" : { "number_of_shards" : 3, "number_of_replicas" : 2 },
"mappings" : { "temp" : { "properties" : { "dashboard" : { "type" : "string" }, "group" : { "type" : "string" }, "title" : { "type" : "string" }, "user" : { "type" : "string" } } }, "dashboard" : { "properties" : { "dashboard" : { "type" : "string" }, "group" : { "type" : "string" }, "title" : { "type" : "string" }, "user" : { "type" : "string" } } } }'

# Kibana4
curl -s -XPUT "http://localhost:9200/TRIBENAME-kibana4" -d '{ "index.mapper.dynamic" : true, "settings" : { "number_of_shards" : 1, "number_of_replicas" : 0 },"mappings" : {"search" : {"_timestamp" : { },"properties" : {"columns" : {"type" : "string"},"description" : {"type" : "string"},"hits" : {"type" : "long"},"kibanaSavedObjectMeta" : {"properties" : {"searchSourceJSON" : {"type" : "string"}}},"sort" : {"type" : "string"},"title" : {"type" : "string"},"version" : {"type" : "long"}}},"dashboard" : {"_timestamp" : { },"properties" : {"description" : {"type" : "string"},"hits" : {"type" : "long"},"kibanaSavedObjectMeta" : {"properties" : {"searchSourceJSON" : {"type" : "string"}}},"optionsJSON" : {"type" : "string"},"panelsJSON" : {"type" : "string"},"timeRestore" : {"type" : "boolean"},"title" : {"type" : "string"},"uiStateJSON" : {"type" : "string"},"version" : {"type" : "long"}}},"visualization" : {"_timestamp" : { },"properties" : {"description" : {"type" : "string"},"kibanaSavedObjectMeta" : {"properties" : {"searchSourceJSON" : {"type" : "string"}}},"savedSearchId" : {"type" : "string"},"title" : {"type" : "string"},"uiStateJSON" : {"type" : "string"},"version" : {"type" : "long"},"visState" : {"type" : "string"}}},"config" : {"_timestamp" : { },"properties" : {"buildNum" : {"type" : "long"},"defaultIndex" : {"type" : "string"}}},"index-pattern" : {"_timestamp" : { },"properties" : {"customFormats" : {"type" : "string"},"fieldFormatMap" : {"type" : "string"},"fields" : {"type" : "string"},"intervalName" : {"type" : "string"},"timeFieldName" : {"type" : "string"},"title" : {"type" : "string"}}}}}'

Toyota Rav4 recall

August 9th, 2012 No comments

11/16/2012 Update: Yep, I got letter from Toyota that my 2010 RAV4 is part of the recall. Crap!

My brother recently alerted me to this. Evidently the Rav4 rear suspension arm might come loose if the nuts holding it together are not tightened correctly.

Here is link to Toyota’s announcement about it.

Check VIN here to see if your Rav4 is part of recall.

August 01, 2012
Toyota Announces Recall of Certain RAV4 and Lexus HS 250h Vehicles

TORRANCE, Calif., August 1, 2012 — Toyota Motor Sales (TMS), U.S.A., Inc., today announced that it will conduct a voluntary safety recall involving 2006 to early 2011 model year RAV4 and 2010 model year Lexus HS 250h vehicles sold in the U.S. No other Toyota or Lexus vehicles are involved.

Approximately 760,000 Toyota RAV4
Approximately 18,000 Lexus HS 250h
Toyota has determined that if the nuts on the rear suspension arm are not tightened following the proper procedure and torque specification during a rear wheel alignment service, excessive play may occur at the threaded portion of the arm, followed by rust formation. If this were to occur, the threaded portion of the rear suspension arm may wear and cause the arm to separate.

Toyota is currently developing a remedy. Once the remedy is available, we will send a notification letter by first class mail advising owners to make an appointment with an authorized Toyota or Lexus dealer to have the remedy performed at no charge.

Detailed information and answers to questions are available to customers at and the Toyota Customer Experience Center (1 800-331-4331) or and Lexus Customer Satisfaction (1 800-255-3987).

Media Contacts:
Vehicle Safety and Quality Communications
Brian R. Lyons (310) 468-2552
John Hanson (310) 468-4718
Katy Soto (310) 468-8068
Toyota Motor Sales, USA, Inc. Media Line (310) 468-5297

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Bingham High School 30th reunion

April 4th, 2012 No comments

Showing my age….

Bingham High school 30 year reunion is coming up on Aug 4th, 2012 (that’s this year folks). It will be from 6pm-9pm MST at Gardner Village, West Jordan, UT.

There is also a Facebook group for this.

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April 4th, 2012 No comments

The following has been making the rounds on Google+. I had a good laugh reading it, so wanted to share here.


16 Things That it Took Me Over 50 Years to Learn (by Dave Barry)

1. Never, under any circumstances, take a sleeping pill and a laxative on the same night.
2. If you had to identify, in one word, the reason why the human race has not achieved, and never will achieve, its full potential, that word would be “meetings.”
3. There is a very fine line between “hobby” and “mental illness.”
4. People who want to share their religious views with you almost never want you to share yours with them.
5. You should not confuse your career with your life.
6. Nobody cares if you can’t dance well. Just get up and dance.
7. Never lick a steak knife.
8. The most destructive force in the universe is gossip.
9. You will never find anybody who can give you a clear and compelling reason why we observe daylight savings time.
10. You should never say anything to a woman that even remotely suggests that you think she’s pregnant unless you can see an actual baby emerging from her at that moment.
11. There comes a time when you should stop expecting other people to make a big deal about your birthday. That time is age eleven.
12. The one thing that unites all human beings, regardless of age, gender, religion, economic status or ethnic background, is that, deep down inside, we ALL believe that we are above average drivers.
13. A person, who is nice to you but rude to the waiter, is not a nice person (This is very important. Pay attention. It never fails.)
14. Your friends love you anyway.
15. Never be afraid to try something new. Remember that a lone amateur built the Ark. A large group of professionals built the Titanic.
16. Final thought for the day: Men are like fine wine. They start out as grapes, and it’s up to the women to stomp the snot out of them until they turn into something acceptable to have dinner with.

— Dave Barry

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