After running into some wacky networking issues at a recent customer engagement, I had a brainstorm about a smart[ish] DHCPd server that could work in conjunction with DNS and static IP assignment to more intelligently fill subnet space.
Here’s the scenario we had:
Lab network space is fairly-heavily populated with static assigned addresses – in a /23 network, ie ~500 available address on the subnet, about 420 addresses were in use.
Not all statically-assigned IPs were registered in DNS.
The in-use addresses were did not leave much contiguous, unused space (little groups of 2 or4 addresses open – not ~80, or even a couple small batches of 20-30 in a row).
DNS was running on a Windows 2012 host.
The problem with using the ISC DHCPd server, as supplied by HPSA, is that while you can configure multipleÂ subnets to hand-out addresses on, you cannot configure multipleÂ rangesÂ on a single subnet. So we were unable to effectively utilize all the little gaps in assigned addresses.
- give a very large range on a given subnet (perhaps all but the gateway and broadcast addresses)
- before handing an address out, in addition to checking the leases file for if it is free, check against DNS to see if it is in use
- if an address is in use because it isÂ static, update the leases file with the statically-assigned informationÂ as if it were assigned dynamically – but give it an unusually-long lease time (eg 1 month instead of 4 hours)
- on a periodic basis (perhaps once an hour, day, week – it should be configurable), scan the whole subnet for in-use addresses (via something like nmapÂ and checking against DNS)
- remove all lease file entries for unused/available IPs
- update lease file entries for used/unavailable IPs, if not already recorded
This would have the advantage of intelligently filling address gaps on a given subnet, and require less interaction between teams that want/need to be able to use DHCP and those that need/want static addresses.
Or maybe what I’m describing has already been solved, and I just don’t know how to find it.
…and a week to go.
Normally, I take about one big break for the book of the face every year – generally when my wife and I take a vacation somewhere
This year we’re upping the ante: while home – and accessible via SMS, email, Twitter, phone, Google+, etc – I’m on a two week Facebook break. And then, excluding some exceptions for special events and the like, both my wife and I are planning to also forgo Facebook on the weekends.
It’s far far too easy to get hooked on electronics and feel like youÂ HAVE to replyÂ instantly whenever that little iOS leash buzzes or your Android tether dings.
As a side note – I have been exceptionally happy with Buffer for maintaining some regularity of social media postings.
Your actions must seem natural and executed with ease. All the toil and practice that go into them, and also all the clever tricks, must be concealed. When you act, act effortlessly, as if you could do much more. Avoid the temptation of the revealing how hard you work – it only raises questions. Teach no one your tricks or they will be used against you. –Robert Greene, The 48 Laws of Power (review)
Let me preface by saying that tipping, as such, in the US and Canada is messed up. There is no reason for businesses to not pay their staff to do their jobs. I shouldn’t be “expected” to supplement their employer’s miserly pay by tipping.
But, since that’s how it currently works, I want to share my philosophy of tipping when going out to eat. It’s pretty simple, really.
- for food: start at 20% of the base bill (not including taxes); minimum $1.50/person
- if you can’t afford to spend an extra $1.50 a person, stay home
- for drinks: $0.50 per beer or shot, $1 per mixed drink; minimum $1
- the simpler rule is $1 for every two simple drinks
- for mixed bills: getting close to 20% covers both previous criteria
- eg a base bill of $26.69 would be a $5 tip (20% is actually $5.32 – but when using cash, either leave a $5, or leave $5 plus the change)
- remember: the waiter likely has to share their tips with the bar tender
- add above and beyond for good-to-exceptional service
The ending is everything. Plan all the way to it, taking into account all the possible consequences, obstacles, and twists of fortune that might reverse your hard work and give the glory to others. By planning to the end you will not be overwhelmed by circumstances and you will know when to stop. Gently guide fortune and help determine the future by thinking far ahead. –Robert Greene, The 48 Laws of Power (review)
There need to be coed and/or men-only adoption conferences.
All the ones I know of are for women only.
For example, my wife went to Created for Care this weekend – a ladies-only event. Maybe I should take her advice and start my own
In follow-up to my last post, which itself was a commentary on an earlier topic, I have the additional steps you need to do the previous procude (which is to edit /opt/opsware/boot/tftpboot/pxelinux.cfg/default):
/etc/init.d/opsware-sas stop smartboot
/etc/init.d/opsware-sas start smartboot
If you are unsure of a course of action, do not attempt it. Your doubts and hesitations will infect your execution. Timidity is dangerous: Better to enter with boldness. Any mistakes you commit through audacity are easily corrected with more audacity. Everyone admires the bold; no one honors the timid. –Robert Greene, The 48 Laws of Power (review)
RSS is far from dead – it’s ubiquitous.
What astonishes me, though, is that not all applications that have a WebUI don’t publish feeds via RSS (or Atom – same difference).
OpenNMS and Nagios (via a plugin) will push alerts via RSS – which is fantastic: there’s no reason everyone shouldn’t be able to filter what alerts they look at. I’m sure some other tools will do this, too.
But why don’t all WebUI-based applications support updates and content via RSS? Several of the applications I routinely work with have no possibility of getting data out with an industry-standard format – they use custom APIs (APIs are excellent – and RESTful ones are better, but they’re no RSS).
What benefits could come from every webapp being RSS-enabled? I can think of a few right-off:
- quick user-by-user customization of content viewing
- user-preferred interface for content viewing
- lighter-weight interface for app access
- quick flexibility
Is you’re developing a webapp, or you’re giving an app a WebUI – make sure you give the ability to get information out via RSS.
Along with some of his other works, such as The Pencil: A History of Design and Circumstance, I’ve found the titles interesting, and the back covers alluring.
Sadly, while theÂ book isn’t bad in and of itself, Petroski’s writing sounds like that of his profession – a professor. His style, while informative, carries the dryness associated with being in academia far too long.
Henry obviously knows a lot about engineering – but his delivery is too formal. Compared to works such as 1421 by Gavin Menzies (review), To Engineer is Human sounds like a graduate thesis. Maybe that was the author’s goal – if it was, he accomplished it.
If it was to make somethingÂ normal folks would like and want to read, I think he failed miserably.