Hi list.
Taking the plunge to setup some test digital ocean (DO) droplets. These aren't to be used for web servers, but to be used to run test apps, and to get a better understanding of actually setting up/plying with some of the different aspects of a small amount of sys admin.
So, that I don't blow it, I thought I'd post here, and perhaps a few of my questions can be answered, saving me psin/headache. And hey, others might learn as well. I've looked over different sites/youtube vids for a good chunk of these questions, but want to make sure I'm going down the right path.
I want to setup a few (4-5) different test servers. I want the servers to be able to communicate with each other via name. I'd also like to be able to access one of the servers by name, to allow me to ssh into the box via name, as opposed to ipaddress.
Everything I've seen suggests that I need a domainName, but I suspect that's due to most people wanting to setup webservers. If I'm setting up a box within DO's ip range, the box(es) shouldn't need an actual domain name should they?? I can understand that for a box to be accessed via/external to DO, it might need a domain name.
+---------------------------------- +
box 1 box 2 box3 <<<------------------ outside boxA (from internet to box3) digital ocean ip world
+-------- ----------------- ----- +
where does the domain name come in? where does the DNS setup come in.. ? box (1-3) will be internal/DO boxes
For each box, I assume I'll have to have a dns entry for each box (ip/name) yes/no?
Once this gets resolved I can test out setting up nfs/mysql servers, and having the ability to access the boxes by name from each other.
Thoughts/comments..
Thanks
Allegedly, on or about 15 January 2016, bruce sent:
I want to setup a few (4-5) different test servers. I want the servers to be able to communicate with each other via name. I'd also like to be able to access one of the servers by name, to allow me to ssh into the box via name, as opposed to ipaddress.
Everything I've seen suggests that I need a domainName, but I suspect that's due to most people wanting to setup webservers. If I'm setting up a box within DO's ip range, the box(es) shouldn't need an actual domain name should they?? I can understand that for a box to be accessed via/external to DO, it might need a domain name.
If the software isn't hardcoded to do a DNS lookup with a server, and will use the system to find out the IP for a name, then you can put your data into each computer's /etc/hosts file. Normally, your computers will consult the hosts file, then do a DNS lookup if the hosts file didn't have an answer. For a three computer system, this isn't too much hard work.
But if they won't consult the hosts file, then you'll need a DNS server. But most things won't require that much effort. Though it does become beneficial when you have quite a number of computers - you only have to configure one central point for all your LAN computer's name resolution.
Populate your hosts file in the usual way. With one line per associated addresses, and space-separated data (ip-address domainname alias-names).
e.g. 192.168.1.2 two.localdomain two
That gives you domain names for things that need a name with at least one dot in it, and short names for things that don't need it (and your own convenience).
If you don't want to go through registering a real domain name, then you need to pick one that will not be in use on the internet. It can cause them problems, it can cause you problems, if you use a pre-existing domain name. You might think you've picked a unique one, but may encounter problems browsing some website which has used it for some of their embedded content, and this will not be obvious to you.
Off the top of my head, I can think of three that shouldn't cause you problems. Using "localdomain", as Fedora already uses. Using "lan", as a gazillion other LANs use. Or making a subdomain of "example.com", which is specifically set up for use with examples.
e.g. lan.example.com.
Having said that, it is very useful to have your own domain name. You make experiments like this much easier on yourself. And you can give yourself a permanent email address that's not tied to your ISP (should you ever want to / need to leave it, you'd lose that address). While you might think your service provider may be around for ever, or may be a good service, experience had taught me otherwise, even the big ones.
Hi Tim. Thanks for the reply.
The goal is to get a basic sys admin understanding of DNS, and how to apply it to a few instances/VMs.. Over time, the number of machines will increase. Simply doing the etc/host isn't reasonable.
On Sat, Jan 16, 2016 at 5:51 AM, Tim ignored_mailbox@yahoo.com.au wrote:
Allegedly, on or about 15 January 2016, bruce sent:
I want to setup a few (4-5) different test servers. I want the servers to be able to communicate with each other via name. I'd also like to be able to access one of the servers by name, to allow me to ssh into the box via name, as opposed to ipaddress.
Everything I've seen suggests that I need a domainName, but I suspect that's due to most people wanting to setup webservers. If I'm setting up a box within DO's ip range, the box(es) shouldn't need an actual domain name should they?? I can understand that for a box to be accessed via/external to DO, it might need a domain name.
If the software isn't hardcoded to do a DNS lookup with a server, and will use the system to find out the IP for a name, then you can put your data into each computer's /etc/hosts file. Normally, your computers will consult the hosts file, then do a DNS lookup if the hosts file didn't have an answer. For a three computer system, this isn't too much hard work.
But if they won't consult the hosts file, then you'll need a DNS server. But most things won't require that much effort. Though it does become beneficial when you have quite a number of computers - you only have to configure one central point for all your LAN computer's name resolution.
Populate your hosts file in the usual way. With one line per associated addresses, and space-separated data (ip-address domainname alias-names).
e.g. 192.168.1.2 two.localdomain two
That gives you domain names for things that need a name with at least one dot in it, and short names for things that don't need it (and your own convenience).
If you don't want to go through registering a real domain name, then you need to pick one that will not be in use on the internet. It can cause them problems, it can cause you problems, if you use a pre-existing domain name. You might think you've picked a unique one, but may encounter problems browsing some website which has used it for some of their embedded content, and this will not be obvious to you.
Off the top of my head, I can think of three that shouldn't cause you problems. Using "localdomain", as Fedora already uses. Using "lan", as a gazillion other LANs use. Or making a subdomain of "example.com", which is specifically set up for use with examples.
e.g. lan.example.com.
Having said that, it is very useful to have your own domain name. You make experiments like this much easier on yourself. And you can give yourself a permanent email address that's not tied to your ISP (should you ever want to / need to leave it, you'd lose that address). While you might think your service provider may be around for ever, or may be a good service, experience had taught me otherwise, even the big ones.
-- [tim@localhost ~]$ uname -rsvp Linux 3.9.10-100.fc17.x86_64 #1 SMP Sun Jul 14 01:31:27 UTC 2013 x86_64
Boilerplate: All mail to my mailbox is automatically deleted, there is no point trying to privately email me, I only get to see the messages posted to the mailing list.
I don't think it's pure coincidence that "officialdom" sounds the same as "official dumb."
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Allegedly, on or about 16 January 2016, bruce sent:
The goal is to get a basic sys admin understanding of DNS, and how to apply it to a few instances/VMs.. Over time, the number of machines will increase. Simply doing the etc/host isn't reasonable.
I that case, I'd say look into learning BIND. It's a complete DNS server as used in various places. I don't think playing with a cut down, or limited feature DNS server is worth the bother. Though the basic one that Fedora has will let it read the /etc/hosts file on that particular machine, for it to resolve queries for.
It all depends on whether you want to learn how to use DNS, or just figure out one particular server software.
You'd approach it in a similar way to my prior message, about either using some commonly used LAN domain names, or registering a real one (which has benefits that you'll appreciate in the future).
Set up DNS records using that name, set up your DNS server to resolve those queries, and to resolve your clients queries about the rest of the web. Set up your clients to use that DNS server. The "domain" or "search" parameter in /etc/resolv.conf will append the domain name to any hostname that you use.
e.g. "ping two" would expand into being treated as if you'd typed "ping two.localdomain".
If you're setting DNS records for your clients, then you need to make sure that they always use the same IP, either by manually setting them that way, or using DHCP to always give them the same IP.
The alternative is have a DNS and DHCP server that talk to each other, and each time the DHCP server gives a machine an IP, it puts the information about it into the DNS server.
Well, actually they're not mutually exclusive ways of doing it. My LAN uses machines in all those ways. The main server has an IP fixed by its own configuration. The usual clients have IPs fixed by the DHCP server. And guests get the full automatic treatment by the DHCP server. With the DHCP server informing all clients of the local DNS server address.
Other than the occasional bit of problem solving, I haven't had to refer to a machine by its numerical IP in many years, I've always used hostnames.
Did you look at docker for your project? Day after day it's becoming more and more in use, it allow simpler (in my opinion) managing if you have multiples instances, even if they're not in the same server On Sat, 16 Jan 2016 at 19:36, Tim ignored_mailbox@yahoo.com.au wrote:
Allegedly, on or about 16 January 2016, bruce sent:
The goal is to get a basic sys admin understanding of DNS, and how to apply it to a few instances/VMs.. Over time, the number of machines will increase. Simply doing the etc/host isn't reasonable.
I that case, I'd say look into learning BIND. It's a complete DNS server as used in various places. I don't think playing with a cut down, or limited feature DNS server is worth the bother. Though the basic one that Fedora has will let it read the /etc/hosts file on that particular machine, for it to resolve queries for.
It all depends on whether you want to learn how to use DNS, or just figure out one particular server software.
You'd approach it in a similar way to my prior message, about either using some commonly used LAN domain names, or registering a real one (which has benefits that you'll appreciate in the future).
Set up DNS records using that name, set up your DNS server to resolve those queries, and to resolve your clients queries about the rest of the web. Set up your clients to use that DNS server. The "domain" or "search" parameter in /etc/resolv.conf will append the domain name to any hostname that you use.
e.g. "ping two" would expand into being treated as if you'd typed "ping two.localdomain".
If you're setting DNS records for your clients, then you need to make sure that they always use the same IP, either by manually setting them that way, or using DHCP to always give them the same IP.
The alternative is have a DNS and DHCP server that talk to each other, and each time the DHCP server gives a machine an IP, it puts the information about it into the DNS server.
Well, actually they're not mutually exclusive ways of doing it. My LAN uses machines in all those ways. The main server has an IP fixed by its own configuration. The usual clients have IPs fixed by the DHCP server. And guests get the full automatic treatment by the DHCP server. With the DHCP server informing all clients of the local DNS server address.
Other than the occasional bit of problem solving, I haven't had to refer to a machine by its numerical IP in many years, I've always used hostnames.
-- [tim@localhost ~]$ uname -rsvp Linux 3.9.10-100.fc17.x86_64 #1 SMP Sun Jul 14 01:31:27 UTC 2013 x86_64
Boilerplate: All mail to my mailbox is automatically deleted, there is no point trying to privately email me, I only get to see the messages posted to the mailing list.
Windows, it's enough to make a grown man cry!
-- users mailing list users@lists.fedoraproject.org To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines Have a question? Ask away: http://ask.fedoraproject.org
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bruce -
thibaut noah -
Tim