Docker toolbox/Virtual Box network interfaces

Talking Windows 8 … trying to create a docker instance … and we would get a message like:

Error setting up host only network on machine start: VirtualBox is
configured with multiple host-only adapters with the same name
"HostInterfaceNetworking-VirtualBox Host-Only Ethernet Adapter".
Please remove one

We had to go to the control panel -> network devices, and THERE we find duplicate interfaces were created. We created one by hand via “./VBoxManage hostonlyif create”, and it was created with a number (#8 in our case). We deleted all but that manually created one and tried to recreate the docker … and we’re on to the next issue.

So THAT is where you need to delete the adapter; from your device manager.

The next problem gives the error: “vboxmanage error failed to open/create the internal network ‘HostInterfaceNetworking-VirtualBox Host-Only Ethernet Adaper”. It appears to be solved for some via:¬† — namely the post by venimus.

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Postman Doesn’t Start After Latest Update

Quick one here — Postman doesn’t seem to want to start on my Windows 8 box after the latest update. Did a good bit of digging, and …. can’t remember where I found this (I’ll provide a reference if I come across it again) but if you right-click and “troubleshoot compatibility problems” it’ll set the compatibility mode to Windows 8. Or, of course, you can set the compatibility mode manually.

It’s a strange issue that without this, you get a blank box with menus that don’t work …. but on a Windows 8 box, setting Windows 8 compatibility, it all works.

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FreeNAS 11 & CentOS VM

Getting back to working on a Linux VM on my home server; I had installed CentOS in a VM but apparently missed some things. My server rebooted due to some updates and I could no longer get the VM to boot. Fortunately … a combination of postings helped me out.

The first issue I had was that I kept booting off the virtual cd, and an attempt was being made at installing the OS again. I just removed the cd definition and I was then booting into a bios-like environment. This YouTube video helped me out there. The video is for ubuntu, but the key was that if you go to the “Boot Maintenance Manager”->”Boot From File”-> next prompt -> “EFI” -> “centos” -> “grubx64.efi” you will be booted into the installation of CentOS that you installed.

From this point, a tip specifically for CentOS was this post here. The key was to copy /boot/efi/EFI/centos/shimx64-centos.efi to /boot/efi/EFI/BOOT/BOOTX64.EFI. Apparently this can be done via a grub command line (another post indicates that “grub-install –efi-directory=/boot/efi –boot-directory=/boot –removable” would work, but I didn’t try it).

In any case, a manual copy of that file, and then reboot … and I’m back in business.

The only other issue I had doing what I’m trying to do required me to set sudo permissions so that my account isn’t prompted for a password. This post led me to the solution for that, in the post by Richipal.


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Quick fix for pgAdmin 4 v3.0 and Windows

I’m looking at switching to pgAdmin 4 v3.0 for interacting with my local postgres database that is used during development, along with a few fellow developers/friends looking at the same. Unfortunately, after installing pgAdmin 4 v3.0 and setting up a Server with the hostname/address as “localhost”, while we can browse the table hierarchy via the tree on the left-hand-side of the screen, if we launch a query window, or ask for the “top 100 rows”, we get nothing.

Fortunately, a hat tip to Fernando Fabreti through this slashdot post did the trick: do NOT use “localhost” as the server name, but use the ip address No idea why it works, but it does, and I can now continue exploring the use of pgAdmin 4 v3.0.

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Quick git bash fork permission denied fix

Just had to post this one. Big kudos’ to the participants in this thread.

We were tracking down an issue where a particular command worked on my laptop, but didn’t on my VM or my buddies corporate laptop. I run a different antivirus than my bud on his corporate laptop … with him running Cylance.

The error we got was:

$ dirname "$(echo "$0" | sed -e 's,\\,/,g')"
 8 [main] bash 6612 fork: child -1 - CreateProcessW failed for 'C:\Home\apps\Git\usr\bin\bash.exe', errno 13
bash: fork: Permission denied

By getting with IT and switching to a developer profile to allow things like git, bash, etc., we’re good and we don’t get that error anymore.

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Postgres as Queue

We have a pretty simple need for a queue, and we’ve chosen to use the database as the queue. Stores send trace logs to our system every minute; in order to not tie them up with a long-running REST call, we log the call to the database, including the payload and any other information from the call so we can pick up the request from the queue later on and process it.

Unfortunately, our first rendition of this resulted in occasional duplicate processing, as multiple nodes both picked up an item for processing. Further research indicated that tightening up the transaction to be of type SERIALIZABLE would work … and it did, but that requires handling a “not serializable” exception from the database when multiple nodes collide obtaining the next bit of work from the queue.

The better fix is simpler than that, actually, but does require Postgres 9.5+. Namely, the use of “SKIP LOCKED”. I’ve read about this in a number of places, but among the best articles is this one:¬†

We haven’t implemented this as of yet (we have a card in our backlog to do so), but this should eliminate some unnecessary exception handling and boost performance a bit (avoiding an extra round trip to the database when a request for the next item fails).

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Eclipse and Conflicting Groovy Versions

Talking to a friend, he reminded me of an issue we had long ago … and he ran into again recently. Occasionally, doing groovy development in Eclipse, the IDE will occasionally complain about a conflicting version for the groovy compiler. Generally, this is due to just a minor revision number, and really shouldn’t be anything to worry about. It is, however, very annoying, and eclipse will just refuse to compile our code.

The fix is pretty simple: just do a “Configure Build Path”, select the Libraries tab, and remove the “Groovy Libraries” selection.

After that, all is good and the minor revision conflict is gone.

It’s been a while since I’ve had to do this; looking through my notes, I’m not sure if I used an online reference for this or not, so … if you came across this before me and I got the information from you, please forgive me for not giving credit where credit is due!

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