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AWS 推出 Scheduled Reserved Instances

Amazon EC2 提供的新玩法,Scheduled Reserved Instances (Scheduled RI):「New – Scheduled Reserved Instances」。

Scheduled RI 可以指定買「某個特定時段」一年,像是每天的凌晨零點到八點之類的,拿來跑 report 這類需求。不過不同於 Standard RI 是不需要另外設定就會自動生效,Scheduled RI 需要開機器時指定才會使用。

不過只會省一些,而不像 Standard RI 可以省的量:

The new Scheduled Reserved Instance model allows you to reserve instances for predefined blocks of time on a recurring basis for a one-year term, with prices that are generally 5 to 10% lower than the equivalent On-Demand rates.


This feature is available today in the US East (Northern Virginia), US West (Oregon), and Europe (Ireland) regions, with support for the C3, C4, M4, and R3 instance types.

就成本來看,應該是屬於最後 optimize 的項目,而不是一開始的最佳化...

EC2 Spot Blocks:固定時間的 Spot Instances

EC2 設計 Spot Instances 提供某些應用程式可以用比較低廉的價錢租用機器,但缺點是隨時可能會中斷,所以程式必須定時記錄進度。

但不是每種應用程式都有辦法這樣做,所以一般遇到不能中斷的還是會用 On-Demand Instances 來處理。而現在 EC2 則提供了 Spot Blocks 來解決這個問題:「New – EC2 Spot Blocks for Defined-Duration Workloads」。

你可以設定 1 到 6 個小時的執行時間,時間到就會自動結束:

In order to make EC2 an even better fit for this type of defined-duration workload, you can now launch Spot instances that will run continuously for a finite duration (1 to 6 hours).

Spot Instances 與 Spot Blocks 是分開競價,大約比 On-Demand 便宜 30%~45%,同時在非尖峰時間另外會有 5% 的優惠:

Pricing is based on the requested duration and the available capacity, and is typically 30% to 45% less than On-Demand, with an additional 5% off during non-peak hours for the region. Spot blocks and Spot instances are priced separately; you can view the current Spot pricing to learn more.

Amazon EC2 預定要推出的 Dedicated Hosts

Amazon EC2 愈定要推出新的購買方案:「Coming Soon – EC2 Dedicated Hosts」。

Dedicated Hosts 的租用是以整台主機為單位,以確保整台實體機器不會有其他人使用,對安全性的要求會比較好。這邊拿 c3.xlarge 來舉例,一次就是八台的費用:(這邊「八台」的數字是未定的,真正的數字要等正式公告上線後才知道)

Each host has room for a predefined number of instances of a particular type. For example, a specific host could have room for eight c3.xlarge instances (this is a number that I made up for this post). After you allocate the host, you can then launch up to eight c3.xlarge instances on it.

會有這樣的需求主要還是因為有些軟體還沒有適當的 cloud-based licensing (授權方式),當 BYOL 時 (Bring Your Own License),會需要能夠對實體機器有更多控制權:

We want to make sure that you can continue to derive value from these licenses after you migrate to AWS. In general, we call this model Bring Your Own License, or BYOL. In order to do this while adhering to the terms of the license, you are going to need to control the mapping of the EC2 instances to the underlying, physical servers.

另外這對於安全性理由也多了個解決方案,像是需要實體分離避開各種 side-channel attack。不過 AWS 之前就有提供其他的方法。

對於軟體有支援 CloudHSM 的,可以考慮直接使用這個解決方案,private key 直接放在 HSM 上,而且 AWS 有符合常見的安全標準。

而另外對於有跟美國政府簽約的數據需求,可以用 AWS GovCloud (US),讓一般人根本接觸不到。

對於一般單位的需求,也可以用 Dedicated Instances 來確保實體機器上只有單一客戶,而這也能買 Reserved Instances 確保使用權,以及對應的折扣。

所以這次 Dedicated Hosts 比較像是商業授權上的需求而產生出來的解決方案,而不是安全性需求...