To ensure that Elastic Compute Service (ECS) instances can run as expected, take note of the following items before you use the instances.
Notes on security responsibilities
Alibaba Cloud and customers share responsibilities for the security of ECS in the cloud. For information about the security responsibilities of Alibaba Cloud and customers for ECS, see Shared security responsibility model of ECS.
Notes on operations
After you create an ECS instance, only you have the administrator permissions on the instance and can log on to the instance.
Do not resell or sublicense the bandwidth that is assigned to your ECS instances without authorization. Failure to comply with the note causes your instances to be stopped, locked, and released.
Do not use your ECS instances for malicious, fraudulent, or illegal activities, such as click farming or fraudulent transactions on e-commerce websites such as Taobao. Failure to comply with the note results in the suspension or termination of your account.
Do not uninstall relevant hardware drivers.
Do not modify the media access control (MAC) addresses of network interface controllers (NICs) unless necessary.
Do not enable SELinux.
ECS instances whose memory size is greater than or equal to 4 GiB must use 64-bit operating systems. A 32-bit operating system can address up to 4 GiB of memory. Alibaba Cloud allows you to create instances that run 64-bit operating systems. The operating system versions that are displayed on the instance buy page prevail. The following 64-bit operating systems are supported:
Alibaba Cloud Linux 64-bit
CoreOS 64-bit
CentOS 64-bit
Debian 64-bit
FreeBSD 64-bit
openSUSE 64-bit
SUSE Linux 64-bit
Ubuntu 64-bit
Red Hat 64-bit
Windows 64-bit
To ensure service continuity and prevent failover-induced service unavailability, we recommend that you configure relevant service software to automatically start on instance startup. If service applications are connected to databases, we recommend that you enable auto-reconnection for the service applications.
We recommend that you do not upgrade the kernel or operating system of an instance.
Specific software or application licenses must be bound to the hardware of ECS instances. After data is migrated from one instance to another, hardware information may change and invalidate the licenses.
Notes on Windows instances
Do not stop the built-in Aliyun Assist Service or shutdownmon.exe process. If you stop the service or process, your ECS instances may fail to be stopped or restarted in the ECS console.
Do not modify the hostname of the domain controller.
We recommend that you do not create custom images by using a virtual machine that acts as a domain controller.
Do not rename, delete, or disable the administrator account on an ECS instance. Such operations may affect the use of the instance.
If your instances use basic disks, we recommend that you do not use the virtual memory. If your instances use ultra disks, standard SSDs, or enhanced SSDs (ESSDs), you can use the virtual memory based on your business requirements.
Proceed with caution when you use the administrator account to resize disks, manage spanned volumes or the registry, and update the system. Failure to comply with the note may result in data loss.
A 32-bit Windows operating system supports up to 4 vCPUs.
Make sure that at least 2 GiB memory is available when you build a website or deploy a web environment on a Windows instance. Instance types that have only one vCPU and 1 GiB of memory do not support MySQL databases.
For information about the usage notes on images and operating systems, see Select an image.
Notes on Linux instances
Do not modify the content of the default /etc/issue file on Linux instances. If you modify the /etc/issue file on a Linux instance and then use the instance to create a custom image, the operating system distribution of the image cannot be recognized. As a result, instances that are created from the image fail to start.
Do not modify the permissions of the directories in the root partition, especially /etc, /sbin, /bin, /boot, /dev, /usr, and /lib. Improper modifications of permissions may cause errors.
Do not rename, delete, or disable the root account.
Do not compile or perform operations on the Linux kernel.
If your instances use basic disks, we recommend that you do not use swap partitions. If your instances use ultra disks, standard SSDs, or ESSDs, you can use swap partitions based on your business requirements.
Proceed with caution when you use the root account to run the fio, mkfs, or fsck command or resize disks. Failure to comply with the note may result in data loss.
For information about the usage notes on images and operating systems, see Select an image.
Limits
For information about the limits on ECS, see Limits.