This topic answers common questions about ENS instances regarding bandwidth, internal network connectivity, traffic security, storage types, resizing, and monitoring.
Do ENS instances use single-line, dual-line, or BGP bandwidth?
ENS instances primarily use single-line bandwidth from telecom providers such as China Telecom, China Unicom, and China Mobile.
Can ENS instances on the same edge node communicate over the internal network?
Yes. ENS instances on the same edge node and within the same network can communicate directly using their internal IP addresses.
Can ENS instances on different edge nodes communicate over the internal network?
No. The network of each edge node is isolated. To communicate between instances on different nodes, you must use the public network.
Do edge nodes support VPC? How can I access a database over the internal network?
Yes, ENS edge nodes support VPC. Instances located on the same edge node and within the same VPC can communicate over the internal network. To access a cloud database, such as ApsaraDB RDS for PostgreSQL, in a central region from an edge node over the internal network, use the edge-cloud wide area network interconnection solution. For details, see Edge-Cloud Wide Area Network Interconnection Solution.
What traffic security solutions does ENS provide?
-
Blackhole filtering: If attack traffic directed at a server exceeds the data center's blackhole threshold, Alibaba Cloud blocks all public network access to that server. The system automatically restores access after the attack subsides. Alibaba Cloud purchases this service from carriers, who impose strict limits on when and how often a block can be removed. Therefore, you cannot manually lift the block and must wait for the system to automatically restore access.
ENS will offer Anti-DDoS Pro / Anti-DDoS Premium in the future to provide enhanced security.
-
Anti-DDoS Basic: A value-added protection service that protects internet-facing servers, including those not hosted on Alibaba Cloud, from service disruptions caused by high-volume DDoS attacks.
Does ENS use cloud disks or local disks?
ENS supports both local disks and ultra cloud disks. The available types vary by edge node.
A local disk resides on a single physical host, which means its reliability is tied to that host. This creates a single point of failure (SPOF) and a risk of data loss. If you require high data reliability, you should implement data redundancy at the application layer.
How do I use ENS to direct users from different regions to specific nodes?
To direct users to specific nodes, you can manually configure access policies in Global Traffic Manager (GTM). For instructions, see Configure an access policy (for example, to route users in southern China to a Fujian node and users in northern China to a Heilongjiang node).
What is the default security group policy?
By default, a security group with no rules allows all traffic.
Can I resize an ENS instance?
Currently, you can only resize subscription ENS instances. To do so, stop the instance in the console and follow the steps in Resize an instance.
Why do I get an error when I use VNC to log in to a bare metal instance?
ENS bare metal instances do not support remote login using VNC.
Monitoring for ENS bare metal instances
ENS bare metal instances do not support online diagnostics or provide monitoring data. If you encounter an issue with your instance, take it offline for maintenance. After maintenance is complete, you can bring the instance back online.
Can I expand an ENS system disk?
No, you cannot expand an ENS system disk. You can only expand data disks. Attempting to expand a system disk causes the instance information not found error.
Why can't I initialize a system disk with a snapshot?
You cannot initialize (reset) a system disk that has a snapshot. You must delete the snapshot before initializing the disk.