How to add second extra network interface on Ubuntu 18.04 VM on OpenStack

I have a public interface on a Ubuntu 18.04 VM hosted by a provider that uses OpenStack. Now I want to add a second extra interface for the internal network. I’m not sure how to do that.

Using the web interface of the hosting provider I can add the internal network. After I add this I can see the network interface but no IP address is assigned. Reboot also doesn’t help here.

So for example ip a shows

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00     inet 127.0.0.1/8 scope host lo        valid_lft forever preferred_lft forever     inet6 ::1/128 scope host         valid_lft forever preferred_lft forever 2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000     link/ether fa:16:3e:e7:0b:19 brd ff:ff:ff:ff:ff:ff     inet (MY PUBLIC IP)/24 brd 185.110.173.255 scope global dynamic ens3        valid_lft 84480sec preferred_lft 84480sec     inet6 fe80::f816:3eff:fee7:b19/64 scope link         valid_lft forever preferred_lft forever 3: ens7: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000     link/ether fa:16:3e:e3:4f:3f brd ff:ff:ff:ff:ff:ff 

My public ip shows up but the interface I added gets no IP address.

I added the ens7 interface to /etc/netplan/50-cloud-init.yaml as follows

# This file is generated from information provided by # the datasource.  Changes to it will not persist across an instance. # To disable cloud-init's network configuration capabilities, write a file # /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following: # network: {config: disabled} network:     version: 2     ethernets:         ens3:             dhcp4: true             match:                 macaddress: fa:16:3e:e7:0b:19             set-name: ens3         ens7:             dhcp4: true             match:                 macaddress: fa:16:3e:e3:4f:3f             set-name: ens7 

When I run netplan apply my SSH connection is immediately disconnected and I can no longer access the machime from the internet.

When I use the console and run ip a I see exactly the results I expected however. ens3 has the correct public IP and ens7 has the correct private ip.

I also have a Ubuntu 16.04 VM. Using that cloud image I was able to do this by editing /etc/network/interfaces.d/50-cloud-init.cfg and adding

auto eth1 iface eth1 inet dhcp 

But now I want to do something similar on Ubuntu 18.04 VM.

Why am I unable to access the machine using SSH from the internet? IP configuration looks okay.

What is the correct way to add a VM to a second internal private network when using an Ubuntu 18.04 cloud image on OpenStack?

BTW, I am using Ubuntu cloud image bionic-server-cloudimg-amd64.img

Install Ubuntu on second SSD

I am currently using a Xiaomi Mi Air 13 laptop which has two slots for SSD drives. In the first one, which came with the computer, I have Windows 10. I have now bought a second SSD for the second slot, where I want to install Ubuntu. I am nos sure if this can be done and how will dual boot work if I do it. I could use some help in the instalation process.

Thanks

Would there be any significant balance implications for letting a player forfeit their action to take a second bonus action? [duplicate]

This question already has an answer here:

  • Which balancing issues, if any, would arise from allowing PCs to spend actions on bonus action features? 4 answers

As the title suggests, I’m wondering if there would be any significant balance implications for letting a player forfeit their action to take an additional bonus action (but not the other way around).

I know there would be balance implications for the other way around so that’s why I said that.

I also know that RAW they’re not at all interchangeable but as a house rule option maybe?

Which database to use? Storing one string every second for several days

I would like to observe some cryptocurrency prices and for that, I want to store a string, everey second in a database for ca. 3 days. The string will vary in length, it will be 2500 characters max. (complete orderbook), sometimes just 50 (prices). I want to analyze the prices later in Python.

Several questions arise for me: 1) Which database would you recommend? I have worked with SQLite and like it so far, but I am unsure whether it’s the most efficient solution, as file sizes get large and reading might be slow. Are there more appropriate solutions? 2) If the string has a special format, e.g. JSON, should my choice from quesiton 1) change – are there special databases which fit well with my use case?

Thank you very much in advance!

Second monitor does not work after disabling? 18.04

I hooked up a second screen to my computer today. It worked at first. Since I don’t need it the whole time, I switched it off and set the screen display settings to only use my HDMI monitor. Now I can’t use the DVI one anymore at all as long as the HDMI one is connected. To be clear, I can see both in the settings and adjust settings, and when I click “apply”, the screen quickly wakes up. But it shows no image, and everything reverts back. It does show a picture before login. What can I do about this? I’m on Ubuntu 18.04.

Doubt on boot options – Installing ubuntu on a second disk

I have windows 10 installed in my SSD as my main OS and just installed Ubuntu 18.04 in a separate hard drive. At the moment the PC would boot windows automatically. If I want to boot Ubuntu I have to select it directly on the BIOS.

The thing is, in the BIOS says that ubuntu’s bootloader is on the SSD (it says something like Ubuntu: P1 Kigston…). Have I done something wrong during the installation?

PS.: While installing Ubuntu, the option “Device for boot loader installation” i chose was the same one I was attempting to install the system (HDD).

Second Order QBF

Consider a universe with two elements 0,1 and a second order formula, i.e. of the form “forall R exists S … such that F”, where R,S are relation symbols of some given arity, and F is some first order formula e.g. “exists x forall y R(x,y)&S(y,x)”.

Further for simplicity assume that the quantifier-free part (the “matrix”) of F is given in disjunctive normal form, and everything is in prenex normal form.

What would be an algorithm to decide satisfiability (or better, list all solutions namely if the formula begins with “exists R” to list all relations that satisfy it) of such second order boolean formula, anything better than brute force in the average case (as probably no one knows to do it better than brute force in the worst case if that’s even possible)? Surely just a reference would be great as well.

Alternatively, if one can point me to a second-order version of the resolution method.