When using Alibaba Cloud SLB, you can set different weights for backend ECS instances. The higher
the weight of a backend ECS instance, the more load will be assigned to it. If an SLB instance has 5
ECS instances in the backend server pool, all of which are healthy. Among these 5 ECS instances, the
weight of ecs_inst1 is set to 100. Which of the following statements is correct?
A
Explanation:
Alibaba Cloud Server Load Balancer (SLB) is a service that distributes network traffic across multiple
ECS instances to improve the service capabilities of applications. SLB supports different load
balancing algorithms, such as round robin, weighted round robin, and least connections. When using
the weighted round robin algorithm, SLB assigns different weights to backend ECS instances based on
their processing capabilities. The higher the weight of a backend ECS instance, the more requests it
will receive from SLB. However, the weight of a backend ECS instance is not the only factor that
determines the load distribution. The number and the weight of other backend ECS instances in the
same server group also affect the load balancing result. Therefore, without knowing the weight
settings of the remaining 4 ECS instances, we cannot tell what would happen to the load distribution
among the 5 ECS instances. The other statements are incorrect because they assume a fixed or
proportional load distribution based on the weight of ecs_inst1, which is not necessarily true.
Reference:
Alibaba Cloud Server Load Balancer
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Alibaba Cloud Computing Exam Question 2022
Server Load Balancer can help protect from
attack.
A
Explanation:
Server Load Balancer (SLB) can help protect from distributed denial-of-service (DDoS) attacks by
distributing network traffic across groups of backend servers to improve the service capability and
application availability. SLB also supports built-in Anti-DDoS services to ensure business
security.
Anti-DDoS services can mitigate DDoS attacks at the Tbit/s level and provide multiple
defense methods, such as blackhole filtering, traffic scrubbing, and access control1
.
In addition, you
can integrate Application Load Balancer (ALB) with Web Application Firewall (WAF) in the console to
ensure security at the application layer and prevent attacks such as SQL
injection2. Reference: 1
:
Server Load Balancer(SLB) - Alibaba Cloud2
:
Associate an EIP protected by
Anti-DDoS Pro/Premium with an ALB instance - Server Load Balancer - Alibaba Cloud Documentation
Center
.
Reference: https://www.alibabacloud.com/help/doc-detail/27539.htm
Which of the following statements to OSS bucket is not correct?
B
Explanation:
A bucket is a container for objects in Object Storage Service (OSS). Every user can create more than
one bucket, but every bucket should have a unique name in OSS. There is no limitation to the
number of objects inside one bucket. However, the bucket name cannot be changed after
creation.
You cannot customize, change, or request a namespace name change1
.
If you want to
modify an object, you must upload a new object with the same name as the existing one to replace
it2. Reference: 3: Create a bucket - Object Storage Service - Alibaba Cloud3 4: Manage objects in a
versioning-enabled bucket - Object Storage Service - Alibaba Cloud4 1: Understanding Object Storage
Namespaces - Oracle1 2: OSS Concepts - Alibaba Object Storage Service Course - Cloud Academy2
Reference: https://www.alibabacloud.com/help/doc-detail/31885.htm?
spm=a2c63.p38356.a3.3.43f03bb9a3KjLl
www.company.com is a newly launched social portal for exchanging automotive information. The
portal is based on PHP, including 10GB of images, and some JavaScripts files. Currently one single ECS
instance is used to host all the application content as well as a MySQL database. With the growing
number of users, the portal is getting slower to load images or respond to user requests. Moreover,
there will be additional 50GB image content uploaded to the portal every week. Which combination
of Alibaba Cloud services below can help resolve the storage and performance issue at the same
time?
A
Explanation:
Object Storage Service (OSS) is a cloud storage service that provides secure, cost-effective, and
scalable storage for various data types, such as images, videos, and documents. OSS can store large
amounts of data and support concurrent access from multiple users. OSS can also integrate with
other Alibaba Cloud services, such as Media Transcoding Service (MTS), Server Load Balancer (SLB),
and Elastic Compute Service (ECS). By using OSS, the portal can offload the storage and delivery of
the image content from the ECS instance, which can improve the performance and availability of the
application.
Content Delivery Network (CDN) is a distributed network that delivers content to users based on
their geographic locations, the origin servers, and the content delivery policies. CDN can accelerate
the delivery of static and dynamic content, such as images, videos, and web pages, by caching the
content at edge nodes that are closer to the users. CDN can also reduce the network latency and
bandwidth consumption, as well as enhance the security and reliability of the content delivery. By
using CDN, the portal can speed up the loading of images and improve the user experience.
Therefore, the combination of OSS and CDN can help resolve the storage and performance issue of
the portal at the same time. The other combinations are not as effective or suitable for the portal’s
scenario. OSS + MTS combination can help with the storage and transcoding of media files, but not
with the delivery of images. OSS + RDS combination can help with the storage and management of
relational databases, but not with the loading of images. OSS + ECS combination can help with the
storage and computing of data, but not with the acceleration of content delivery.
Reference:
Alibaba Cloud Object Storage Service
Alibaba Cloud Content Delivery Network
ACA Cloud Computing Certification Exam Preparation Course
Which method is not supported by OSS to create a bucket?
B
Explanation:
ECS instance filesystem directory operation is not a supported method to create a bucket in OSS. A
bucket is a container for objects in OSS, and it is not related to the filesystem of an ECS instance.
To
create a bucket in OSS, you can use one of the following methods1
:
through OSS API/SDK: You can use the OSS API or SDK to call the PutBucket operation to create a
bucket.
The OSS API and SDK support various programming languages, such as Java, Python, PHP, C#,
and Node.js2
.
through oss cmd tool: You can use the oss cmd tool, which is a command-line tool based on the OSS
SDK for Python, to create a bucket by using the ossutil mb command3
.
through cloud console: You can use the Alibaba Cloud console to create a bucket by following the
steps in the documentation4. Reference: 1
:
Create buckets - Object Storage Service - Alibaba Cloud
Documentation Center2
:
PutBucket - API Reference| Alibaba Cloud Documentation Center3
:
Create a
bucket - OSSUTIL User Guide| Alibaba Cloud Documentation Center4
:
Create a bucket - Object
Storage Service - Alibaba Cloud Documentation Center
.
A large shopping mall deploys a new video surveillance system. The five-floor building in which the
mall is located installed 35 HD cameras to monitor the major exits. The surveillance system is
deployed on an ECS instance, which has four 2 TB data disks to store video data.
However, video data grows rapidly and the engineers find that the ECS will run out of storage space
within 2 weeks.
In this case,
product is thought to be the best solution for addressing the storage challenge while
ensuring quick access to historical video data when needed.
C
Explanation:
A large shopping mall deploys a new video surveillance system. The five-floor building in which the
mall is located installed 35 HD cameras to monitor the major exits. The surveillance system is
deployed on an ECS instance, which has four 2 TB data disks to store video data.
However, video data grows rapidly and the engineers find that the ECS will run out of storage space
within 2 weeks.
In this case, OSS is thought to be the best solution for addressing the storage challenge while
ensuring quick access to historical video data when needed. OSS is a cloud-based object storage
service that provides massive, secure, low-cost, and highly reliable storage for unstructured data
such as images, videos, and documents. OSS can store any amount of data and scale up or down on
demand. OSS also supports direct video stream storage capabilities, removing the need for a video
segmentation cluster. OSS can be accessed through RESTful APIs, SDKs, or web consoles, and can be
integrated with other Alibaba Cloud services such as CDN, ECS, and SLB. OSS provides various storage
classes for different data storage scenarios, from hot data storage to cold data storage.
For video
surveillance data, the Infrequent Access (IA) or Archive storage classes can be used to reduce the
storage cost while maintaining high data durability and availability123. Reference: 1: Alibaba Cloud
Multimedia Solutions | Video Monitoring & Surveillance1 2: Overview - Object Storage Service -
Alibaba Cloud2 3
: OSS Concepts - Alibaba Object Storage Service Course - Cloud Academy
Which of the following statements about file uploading to OSS strategy is not correct?
A
Explanation:
Alibaba Cloud OSS service provides different methods for file uploading, such as simple upload,
multipart upload, append upload, and resumable upload1
. However, not all of these methods
support resuming from break point, which is a feature that allows you to resume an interrupted
upload from where it left off.
The only method that supports resuming from break point is resumable
upload, which is based on multipart upload and uses a checkpoint file to record the upload
progress2
. The other methods do not support resuming from break point, and will either overwrite
or append to the existing object if the upload is interrupted and retried.
Reference: 1: Alibaba Cloud Academy, “OSS Upload Methods”,
https://edu.alibabacloud.com/elearning/lesson/ACA-Cloud-Computing-Certification/lesson-2-oss-
upload-methods 2
: Alibaba Cloud, “Resumable upload”, https://www.alibabacloud.com/help/doc-
detail/31991.htm
Which of the following scenarios is applicable to use RDS read-only instances?
B
Explanation:
ApsaraDB RDS for MySQL is a cloud-based relational database service that provides secure, cost-
effective, and scalable database solutions for various applications. RDS for MySQL supports creating
read-only instances that are synchronized with the primary instance in real time. Read-only instances
can handle read requests from applications and reduce the read pressure on the primary instance.
This can improve the performance and availability of the database system. Read-only instances can
also be used for scenarios such as report analysis, data backup, and disaster recovery.
Reference:
Overview of read-only ApsaraDB RDS for MySQL instances
ACA Cloud Computing Certification Exam Preparation Course
Alibaba Cloud Computing Exam Question 2022
SQL injection is a common application layer attack, usually through building special input parameters
and pass it to web applications to steal or sabotage the application dat
a. Which of the following is the target for SQL injection?
B
Explanation:
SQL injection is a common application layer attack that targets the database of a web application.
SQL injection exploits a security vulnerability in the application’s software, such as incorrect filtering
of user input, that allows an attacker to send malicious SQL statements to the database.
These
statements can then be executed to steal, modify, or delete data, or even execute commands on the
server1
.
SQL injection can also bypass authentication and authorization mechanisms, and sometimes
even impersonate or damage the underlying system2
.
SQL injection is one of the most common and
dangerous web attacks, and it can cause serious damage to the confidentiality, integrity, and
availability of web applications3. Reference: 1
:
SQL Injection - OWASP2
:
SQL Injection - Web
Application Firewall - Alibaba Cloud Documentation Center3
:
Web Application Firewall:What is WAF?
- Alibaba Cloud
.
Reference: https://www.rapid7.com/fundamentals/sql-injection-attacks/
A company wants to use Alibaba Cloud service to replace their self-built database, which of the
following services should it choose?
A
Explanation:
A company wants to use Alibaba Cloud service to replace their self-built database, which of the
following services should it choose?
The best answer is ApsaraDB for RDS, which is a stable, reliable,
cost-effective, and scalable online database service that supports most mainstream database
engines, including MySQL, SQL Server, PostgreSQL, PPAS (highly compatible with Oracle), and
MariaDB1
.
ApsaraDB for RDS is based on the Apsara Distributed File System and high-performance
SSDs of Alibaba Cloud, and provides various features such as backup and recovery, performance
monitoring, security, and disaster recovery2
. By using ApsaraDB for RDS, the company can reduce
the complexity and cost of database management, and focus on their core business.
The other options are not suitable for replacing a self-built database. Server Load Balancer (SLB) is a
service that distributes traffic among multiple ECS instances according to the configured forwarding
rules.
It can be used to balance the load and improve the service availability and fault tolerance of
applications3
. Alibaba Cloud CDN (Content Delivery Network) is a service that delivers content from
origin servers to edge nodes, and accelerates the response to user requests.
It can be used to
improve the user experience and reduce the bandwidth consumption of origin servers4
.
Deploying
more ECS instances is a way to increase the computing resources and scalability of applications, but it
does not provide a database service5. Reference: 1
: What is ApsaraDB RDS?
- ApsaraDB RDS - Alibaba
Cloud1 2
: ApsaraDB RDS:What is ApsaraDB RDS?
- Alibaba Cloud2 3: Server Load Balancer - Alibaba
Cloud Documentation Center3 4: Alibaba Cloud CDN - Alibaba Cloud4 5: Elastic Compute Service
(ECS) - Alibaba Cloud5