Tag Archives: error

Azure VM Unresponsive, Can’t SSH

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My VM Was Non-Responsive

Today I had an Azure virtual machine go down very unexpectedly.

I received error reports from users and tried to go to the related service endpoint myself… and sure enough, it didn’t come up.  Then, I tried to ssh onto the VM and I couldn’t.

I hopped into the Azure portal, went to the VM, and things actually looked alright… it wasn’t stopped, or de-allocated, or anything.

Why?

After multiple minutes of digging around the Azure portal for more information, suddenly the “Activity Log” popped up with a new entry.   This was relatively disconcerting as the issue had been reported over half an hour ago and I had been on the portal for multiple minutes.

The activity log said I had a “health event” which was “updated”.  Upon expanding it, I could see more events that had been “in progress”.  When you click the “in progress” event, you can get JSON for it and look into the details.  In my case, the bottom of the details said this:

    "properties": {
        "title": "We're sorry, your virtual machine isn't available because an unexpected failure on the host server",
        "details": null,
        "currentHealthStatus": "Unavailable",
        "previousHealthStatus": "Unknown",
        "type": "Downtime",
        "cause": "PlatformInitiated"
    }

So, the physical host which was running my VM in azure died. Azure automatically noticed this and moved it to a new physical host, though much slower than I would have appreciated.

The VM came up after a few more minutes and all was right with the world. So… the moral of the story is that if your VM is unresponsive, it may be because the host died, and you may have to wait quite a while to see information on that in the activity log. But it does auto resolve apparently which is nice.

Snowflake SQL compilation error: Object does not exist – Schema / Case Sensitive

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Recently I was having strange issues while trying to grant a role access to a database schema in snowflake.

The schema was manually created after a migration from another database, and its name was in lower-case – e.g. MYDATABASE.”dbo”, “dbo” being the schema name.

Auto Upper Case + Schema Case Sensitivity

What I realized after a short while was that all SQL identifiers you place into Snowflake SQL are automatically made upper case.  Snowflake cares about schema case sensitivity though.

So, unless you’ve been going around and adding double-quotes around all your database/schema/table names while creating them, almost everything you have will be in upper case.

When you do create things in lower-case manually with quoting, you have to go around adding quotes to them in every query to ensure they are actually given in lower-case to the database.  For example, SELECT * FROM mydatabase.dbo.mytable will implicitly become SELECT * FROM MYDATABASE.DBO.MYTABLE.  So, if “dbo” is the real name and not “DBO” for the schema, you actually need to do SELECT * FROM MYDATABASE.”dbo”.MYTABLE instead.

Note, this assumes MYDATABASE and MYTABLE were created in upper-case or without quoting.

Final Thoughts

I personally feel that you should avoid quoting and let everything be upper case.  If you did have to create things in lower-case, then I suggest always using quoting everywhere.  Anything in between the two will get confusing.

Docker + Windows 10 – Volume Mount Shows No Files // Firewall

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I wasted roughly an hour on this two separate times now.  Basically, my docker volume mount would stop showing files.

I dug through endless git hub pages and error reports, tried making the docker NAT private and everything… but the problem ended up being that I went home from work and was using my VPN!

So, before spending too much time on the complicated solutions you find online; just start by disabling your VPN if you have one running and see if that helps first.