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Docker Container Storage and Registries: How to Store, Manage, and Secure Your Images

Docker Container Storage and Registries: How to Store, Manage, and Secure Your Images
Hostman Team
Technical writer
Infrastructure

Docker containerization offers many benefits, one of which is image layering, enabling fast container generation. However, containers have limitations — for instance, persistent data needs careful planning, as all data within a container is lost when it's destroyed. In this article, we’ll look at how to solve this issue using Docker’s native solution called Docker Volumes, which allows the creation of persistent Docker container storage.

What Happens to Data Written Inside a Container

To begin, let’s open a shell inside a container using the following command:

docker run -it --rm busybox

Now let’s try writing some data to the container:

echo "Hostman" > /tmp/data
cat /tmp/data

Hostman

We can see that the data is written, but where exactly? If you're familiar with Docker, you might know that images are structured like onions — layers stacked on top of each other, with the final layer finalizing the image. Each layer can only be written once and becomes read-only afterward. When a container is created, Docker adds another layer for handling write operations.

Since container lifespans are limited, all data disappears once the container is gone. This can be a serious problem if the container holds valuable information. To solve this, Docker provides a solution called Docker Volumes. Let’s look at what it is and how it works.

Docker Volumes

Docker Volumes provide developers with persistent storage for containers. This tool decouples data from the container’s lifecycle, allowing access to container data at any time. As a result, data written inside containers remains available even after the container is destroyed, and it can be reused by other containers. This is a useful solution for sharing data between Docker containers and also enables new containers to connect to the existing storage.

How Docker Volumes Work

A directory is created on the server and then mounted into one or more containers. This directory is independent because it is not included in the Docker image layer structure, which allows it to bypass the read-only restriction of the image layers for containers that include such a directory.

To create a volume, use the following command:

docker volume create

Now, let’s check its location using:

docker volume inspect volume_name

The volume name usually consists of a long alphanumeric string. In response, Docker will display information such as the time the volume was created and other metadata, including the Mountpoint. This line shows the path to the volume. To view the data stored in the volume, simply open the specified directory.

There are also other ways to create a Docker Volume. For example, the -v option can be added directly during container startup, allowing you to create a volume on the fly:

docker run -it --rm -v newdata:/data busybox

Let’s break down what’s happening here:

The -v argument follows a specific syntax, indicated by the colon right after the volume name (in this case, we chose a very creative name, newdata). After the colon, the mount path inside the container is specified. Now, you can write data to this path, for example:

echo "Cloud" > /data/cloud

Data written this way can easily be found at the mount path.

As seen in the example above, the volume name is not arbitrary — it matches the name we provided using -v. However, Docker Volumes also allow for randomly generated names, which are always unique to each host. If you’re assigning names manually, make sure they are also unique.

Now, run the command:

docker volume ls

If the volume appears in the list, it means any number of other containers can use it. To test this, you can run:

docker run -it --rm -v newdata:/data busybox

Then write something to the volume. Next, start another container using the exact same command and you’ll see that the data is still there and accessible — meaning it can be reused.

Docker Volumes in Practice

Now let’s take a look at how Docker Volumes can be used in practice. Suppose we're developing an application to collect specific types of data — let’s say football statistics. We gather this data and plan to use it later for analysis — for example, to assess players’ transfer market values or for betting predictions. Let’s call our application FootballStats.

Preserving Data After Container Removal

Obviously, if we don’t use Docker Volumes, all the collected statistics will simply be lost as soon as the container that stored them is destroyed. Therefore, we need to store the data in volumes so it can be reused later. To do this, we use the familiar -v option: 

-v footballstats:/dir/footballstats

This will allow us to store match statistics in the /dir/footballstats directory, on top of all container layers.

Sharing Data

Suppose the FootballStats container has already gathered a certain amount of data, and now it's time to analyze it. For instance, we might want to find out how a particular team performed in the latest national championship or how a specific player did — goals, assists, cards, etc.

To do this, we can mount our volume into a new container, which we’ll call FootballStats-Analytics. The key advantage of this setup is that the new container can read the data without interfering with the original FootballStats container’s ongoing data collection. At the same time, analysis of the incoming data can be performed using defined parameters and algorithms.

This information can be stored anywhere, either in the existing volume or a new one, if needed.

Other Types of Mounts

In addition to standard volumes, Docker Volumes also supports other types of mounts designed to solve specialized tasks:

Bind Mount

Bind mounts are used to attach an existing path on the host to a container. This is useful for including configuration files, datasets, or static assets from websites. To specify directories for mounting into the container, use the --mount option with the syntax <host path>:<container path>.

Tmpfs Mount

Tmpfs mounts serve the opposite purpose of regular Docker Volumes — they do not persist data after the container is destroyed. This can be useful for developers who perform extensive logging. In such cases, continuously writing temporary data to disk can significantly degrade system performance. The --tmpfs option creates temporary in-memory directories, avoiding constant access to the file system.

Drivers

Docker Volume Drivers are a powerful tool that enable flexible volume management. They allow you to specify various storage options, the most important being the storage location — which can be local or remote, even outside the physical or virtual infrastructure of the provider. This ensures that data can survive not only the destruction of the container but even the shutdown of the host itself.

Conclusion

So, we’ve learned how to create and manage storage using Docker Volumes. For more information on how to modify container storage in Docker, refer to the platform’s official documentation

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Networking Features Networking in vCloud Director supports dynamic routing, distributed firewalls, hybrid cloud integration, and flexible traffic distribution. Many of these features are now standard in the newer versions of Cloud Director. If you don’t already have some of them, you may need to upgrade your NSX Edge and convert it to an Advanced Gateway in the UI. Dynamic routing improves reliability by eliminating manual route configuration. You can also define custom routing rules based on IP/MAC addresses or groups of servers. With NSX Edge load balancing, incoming traffic can be distributed evenly across pools of VMs selected by IP, improving scalability and performance. Access Control and More You can create custom user roles in the Cloud Director UI to control access tailored to organizational needs. VMs can be pinned to specific ESXi host groups (affinity rules), which helps with licensing or performance. 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25 November 2025 · 5 min to read
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Why Developers Use the Cloud: Capabilities and Advantages

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Experienced professionals may need retraining, whereas younger personnel who learn cloud technologies from the start do not face such challenges. Speed Software development often requires significant time and effort for application testing. Applications must be verified across multiple platforms, resolutions, and device types. Maintaining local machines dedicated to testing is inefficient. Cloud computing solves this by enabling rapid deployment of virtually any environment, isolated from other projects, ensuring it does not interfere with team development. High deployment speed and access to cloud services also encourage IT startups to launch almost “from scratch,” with minimal resource investment. The advantages of cloud services are especially critical when development volumes periodically expand. Purchasing hardware consumes a developer’s most valuable resource: time. 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It is also worth noting that both platforms are free, but MySQL has several commercial editions, which can sometimes lead to additional expenses. Programming Languages Both systems support a wide range of programming languages. Among the popular ones are C++, Java, Python, lua, and PHP. Therefore, a company’s development team will not face difficulties implementing features in either system. Operating Systems MySQL is a more universal system that runs on Windows, Linux, macOS, and several other operating systems. PostgreSQL was originally designed for Linux, but with the REST API interface, it becomes an equally universal solution that operates on any OS. Data Processing PostgreSQL provides more capabilities for data processing. For example, a cursor is used for moving through table data, and responses are written to the memory of the database server rather than the client, as in MySQL. PostgreSQL also allows building indexes simultaneously for several columns. It supports different index types, allowing work with multiple data types. This database also supports regular expressions in queries. However, new fields in PostgreSQL can only be added at the end of a table. Parallel data processing is better organized in PostgreSQL because the platform has a built-in implementation of MVCC (multiversion concurrency control). MVCC can also be supported in MySQL, but only if InnoDB is used. Concerning replication, PostgreSQL supports logical, streaming, and bidirectional replication, while MySQL supports circular replication as well as master-master and master-standby. Replication refers to copying data between databases located on different servers. PostgreSQL and MySQL: Performance Comparison Testing is fair only when comparing two clean, “out-of-the-box” systems. Indexed testing provides the following results: Insertion: PostgreSQL is more than 2.7× faster, processing a 400,000-record database in 5.5 seconds versus 15 seconds for MySQL. Inner join: PostgreSQL processes 400,000 records in 1.1 seconds, MySQL in 2.8 seconds: a gain of more than 2.5×. Indexed sorting: PostgreSQL processes the same number of records in 0.9 seconds, MySQL in 1.5 seconds. Grouping: For the same 400,000-record database, PostgreSQL achieves 0.35 seconds, MySQL 0.52 seconds. Indexed selection: PostgreSQL is 2× faster: 0.6 seconds vs. 1.2 seconds. When it comes to updating data, PostgreSQL’s update time increases gradually as the number of records grows, while MySQL processes them in roughly the same time, starting from 100,000 records. This is due to different data-storage implementations. Nevertheless, PostgreSQL holds a significant advantage over MySQL even with large data volumes: 3.5 seconds versus 9.5 seconds for 400,000 records—more than 2.7× faster. Without indexes, PostgreSQL also shows surprisingly high performance, processing a 400,000-record database in 1.3, 0.7, and 2.2 seconds for inner join, selection, and update operations, respectively. Thus, PostgreSQL delivers an average performance advantage of about 2× (2.06). Although MySQL was originally positioned as a high-performance platform, constant optimization by the PostgreSQL development team has resulted in greater efficiency. Advantages for Developers Here we consider only the unique features characteristic of each platform. Therefore, we will not discuss support for MVCC or ACID, as these features are present in both systems. From a developer’s perspective, MySQL is advantageous because it: Provides increased flexibility and is easily scalable, with more than ten storage engines based on different data-storage algorithms. Handles small read-oriented databases more efficiently (i.e., without frequent writes). Is easier to manage and maintain, because it requires less configuration and fewer preparatory steps before starting work. From a developer’s perspective, PostgreSQL is advantageous because it: Offers an object-oriented approach to data, enabling inheritance and allowing the creation of more complex table structures that do not fit the traditional relational model. Handles write-oriented databases better, including validation of written data. Supports object-oriented programming features, enabling work with NoSQL-style data, including XML and JSON formats. Can support databases without limitations on data volume. Some companies use PostgreSQL to run databases as large as several petabytes. PostgreSQL and MySQL Comparison For clarity, the main features of both systems can be presented in a table:   PostgreSQL MySQL Supported OS Solaris, Windows, Linux, OS X, Unix, HP-UX Solaris, Windows, Linux, OS X, FreeBSD Use cases Large databases with complex queries (e.g., Big Data) Lighter databases (e.g., websites and applications) Data types Supports advanced data types, including arrays and hstore Supports standard SQL data types Table inheritance Yes No Triggers Supports triggers for a wide range of commands Limited trigger support Storage engines Single (Storage Engine) Multiple As we can see, several features are implemented only in PostgreSQL. Both systems support ODBC, JDBC, CTE (common table expressions), declarative partitioning, GIS, SRS, window functions, and many other features. Conclusion Each system has its strengths. MySQL handles horizontal scaling well and is easier to configure and manage. However, if you expect database expansion or plan to work with different data types, it is better to consider implementing PostgreSQL in advance. Moreover, PostgreSQL is a fully free solution, so companies with limited budgets can use it without fear of unnecessary costs.
24 November 2025 · 6 min to read

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